A while back, I got a hermit crab, Alex Mercer, mostly because I figured I'd never figure out the damn thing's gender, and I thought its namesake was neat. Well, one day, Alex Mercer was crawling up and down my arm, and because he was at danger of falling, I picked him up by the shell to move him some place safer, but it turns out he was less than happy about that, because he began to flail and stretched himself out far enough to let me take a peek at the part of his underbelly normally in the shell. I did a bit of online sleuthing, and got Alex Mercer to flash me again. That's how I found out Alex Mercer was a woman. As for why I named a crustacean the size of a ping pong ball after a cannibalistic sociopath, all I can say is that I'm a strange little girl, and Alex is my dream-pet.

Many years ago, this troper received two female guinea pigs as a birthday present. A few months later, one was visibly pregnant and the other was a proud father.

This troper used to give gender-neutral names to her guinea pigs due to the difficulty of determining their sex.

In This Troper's version of the story, they were his sister's gerbils, and it later turned out that she'd lied to mom about their genders because she wanted to breed them. Unfortunately, they were also brother and sister, so there was a higher than usual incidence of club feet.

Rabbits. Fortunately we were able to find homes to all of them.

Same, but with gerbils.

Same thing happened to this troper.We ended up keeping the mom and one of the supposedly female babies,but it turns out the one we kept was actually a male, and end up with another set of pups.

Wait... what?

It's actually not uncommon for rodents to mate with their progeny once said child is 'of age'. It's also not uncommon for dog and cat breeders to mix a parent with a child to get desired traits for a litter.

The opposite (without the pregnancy, obviously) happened to @/GracieLizzie's family. We named a cat after Willow Rosenburg, who turned out to be a tomcat, but luckily Willow is a fairly gender-neutral name. Not so for the cat from up the street, who is a tomcat called Phoebe.

@/{{Sikon}}: Heh, happened to us too, and again it was a male cat mistaken for a female.

One @/UnknownTroper had a female rabbit named Fred, for that reason.

The @/ManCalledTrue once had a cat named Lazy that the family thought was female until he noticed the rather... obvious equipment. In their defense, Lazy was a very shaggy-haired cat. No renaming was necessary due to his habit of giving his pets descriptive (gender-neutral) names.

Never, ever, EVER get your Russian Dwarf hamster a friend. It doesn't matter how lonely she seems. This troper had try to take care of some 30+ descendants of her two 'female' hamsters.

This troper's family once had a rabbit they thought was male and were happy to let play with the male rabbit next door. The actually female rabbit ended up with a lot of babies.

And this troper and her family thought their cat Squeak was female for several months, until one day he decided to show off the equipment.

This troper's year old cat had her first litter of one, which her dad declared to be a girl. (And this is a man who wouldn't be squeamish about looking, mind you.) The vet told us when we took both cats to the vet. Luckily, Connie is easily shortened to Con.

This troper heard about a person who was living with his mother, his mother-in-law, his wife and his ''three daughters''. Frustrated, he bought a dog so that he would not be the only male being in the house. See where this is going?

This troper had a co-worker who told her all about her mother-in-law's ordeal with a pet parrot, which included references to ''him'' laying an egg. The mother-in-law thought for ages that the parrot was a male, and, though she obviously learned otherwise, kept the name, Poncho, and continued to refer to it as a "he".

This troper's brother has a pet snake, named Jax, because we believed it to be a male. Then it started laying eggs...

This troper brought two bearded dragons, I named the male Colin, and the female Lisa. 2 weeks later we found that "she" was in fact a "he", when Lisa started to show off the equipment. Some days I REALLY wish that I had given them gender neutral names, to avoid people asking why a male animal has a name like Lisa..

No pregnancy involved, but this troper and her mother were once given a white lop-eared rabbit which was allegedly female. Upon introducing the new rabbit to our other, confirmed female, rabbit, "she" tried to mount the other. Fortunately the bunny hadn't received an official name yet - "Alice" was the current placeholder, hence he was dubbed an Alastair.

Actually, our three really-definitely-female guinea pigs (no babies after a year) sometimes do a bit of mounting. We gave them gender-neutral names just in case, though.

Female rabbits will mount other rabbits. It's a dominance thing. If you watch, you can see the other rabbit getting REALLY angry about it.

This troper has encountered two of these: her grandparents' cat "Caroline" and her neighbor's cat "Ariel" both turned out to be males. (They both kept the feminine monikers.)

Actually, Ariel was an exclusively masculine name until The Little Mermaid came out (Ariele/Arielle being the female variant)

This troper's mother once had a long-haired cat named Purina, which actually turned out to be male, for the reverse of this trope.

This troper's aunt never really owned a dog but ended up having to raise a pit bull from birth (the mother attacked the litter and it was the only one that lived). So they named the dog Zorro. When we knowing more about dogs pointed out that it was missing certain equipment the dog's name was quickly changed to Lola. It's not her fault she just thought the dog was a late bloomer.

This troper has a bird named Elvis, that we assumed to be male until he began laying eggs...

There was no pregnancy involved, but this troper still named her old guinea pig Merja (which is a Finnish variant of Mary) before discovering she was a he. The name stuck anyway.

Bird owners' lives are complicated by the fact that, when there's any difference at ''all'' (and in most parrots, there isn't), a juvenile male's markings are the same as those of the female, juvenile or adult. Added to this the fact that many pet-store birds are sold before their first adult molt, and, well, suffice to say, this troper's pet cockatiel was given a gender-neutral name. (Later confirmed female by way of egg-laying.)

For those who do want to know if their parrot is Polly or Paulie (especially if it's not of a species that shows any difference between sexes other than vague behavioral cues), DNA blood tests are the way to be sure.

Just about the only parrot that is obvious about its gender from the moment its feathers start coming in is the Eclectus. Males are green with red underwings, and females are scarlet and blue. The differences are so striking that naturalists once thought that they were two different species.

@/{{Seanette}} has had a couple of experiences like this: in one case, when she was about six, her family acquired a rather tough tomcat who was named "Attila". "He" got renamed "Matilda" in a hurry when "his" pregnancy became unmistakable. The other instance, a few years ago, involved a ringneck dove who adopted her household. Available evidence, such as how loudly and how much "he" cooed, led to the conclusion the bird was male. "He" was named Avery. Even a vet tech neighbor with dove experience was sure Avery was male, right up until the morning the wreckage of an egg was discovered in "his" cage. She was duly renamed to Ava, and has apparently decided that Seanette, the only other female in the household, is her mate (other household members are a male human and a male cat).

In a very strange coincidence, @/{{Heleentje}}'s aunt's first cat was supposed to be a tomcat, but she wanted to name 'him' Natasha. Natasha did turn out to be female, so the name (retroactively) fit.

This troper's grandmother is in the possession of a male tortoise named Esmerelda for just this reason. This troper has forgotten which of the many owners discovered the error (it's a very, very old tortoise that's outlived many owners, including this troper's grandfather), but it was probably discovered along with its affinity for leather shoes and wheels.

This troper's brother and sister-in-law once adopted a shelter cat named Bo, whom they were assured was a neutered male. Shortly afterward, they noticed Bo was behaving strangely, meowing constantly and rubbing his butt against things. They took him to the vet, who explained Bo was in heat--"he" was a girl, and an unspayed one at that. Since the shelter in question sterilizes all its animals as a matter of policy, we're still not sure how they managed to miss this.

Another shelter mixup story: a friend of mine adopted a "female" cat and took "her" in for a spay, only to find out (after the poor cat had been shaved for surgery) that ''he'' was already neutered.

This troper has two friends with a bunny rabbit they had planned to name Leilani, in a strange series of events having to do with basketball and fan nicknames. Unfortunately for their cunning plan, the bunny appears to be male. That may not stop them, though.

Happened to this troper's best friend the week after she brought home a new pet hamster; one which the shop had assured her was chubby but decidedly male.

When this troper was a little girl, her parents bought two rabbits and were assured that they were both male and there was absolutely no possibilty of baby rabbits. One of the rabbits gave birth to a litter of stillborn babies a couple of months later. But the really weird thing was, we put the rabbits in separate cages after we deduced the female was pregnant- only to have her turn up pregnant a ''second time'' with no opportunity for them to have copulated again. We were fairly certain it wasn't an immaculate conception, so we made inquiries, and it turns out rabbits can concieve ''multiple times on one intercourse.'' I am so not making this up. The second litter of babies was very healthy.

This troper had a fish named Edd (and one named Ed and another named Eddy). She renamed it Edna after it had babies.

A friend of This Troper and her boyfriend had this happen to her cat, whom they first though of as female. It turned out kitty was a boy.

This troper's family was very sad when our kitten Luella got hit by a car. But we couldn't help but laugh when the vet told us Luella was actually a Lou.

Inverted: This editor had a male cat named Molly. The rest of his family tried to rename him "Mauley" after TheReveal, but it didn't take.

This troper's family had a cat named Pancho. "He" was attacked by a dog and taken to the vet. Pancho survived, but the kittens weren't so lucky...

"Zeke" turned out to be a female cat. She actually ''couldn't'' get pregnant for some reason, but helped nurse her nieces and nephews (and probably some half-siblings as well, considering that mother cat Gypsy seemed to ''always'' be pregnant...) Later, this was gender-inverted with a male cat called Elsa.

This troper is glad he's a dog person.

Uh...dogs aren't a OneGenderRace...unless you mean that your 'male' dog had a lot of puppies?

Dogs are much, ''much'' easier to determine the gender for than most house pets.

The dangly parts ''dangle''.

Haha! ''"Dangly parts".''

This troper bought a hamster at the pet store and was told it was a male. She examined it at home and noticed it had, erm, girlyparts instead. Said hamster apparently was in the males' cage for a while and ended up with two tiny hamster babies, born in this troper's cage a few days after the purchase. Quite surprising, to say the least, they were slightly larger than your average jelly bean, pink, slightly see-through, and blind. Once their eyes opened and they got hair they were extremely cute.

This troper had the same experience as a child, except that we didn't discover our allegedly male hamster was a girl until she gave birth. This was really exciting...except that the next day, while troper was at school, Mama Hamster ate the babies. Ewww.

This troper's sister once had a budgie called Putte, who turned out to be female. This troper still has trouble thinking of that name as masculine.

There's a legend that a Swedish cavalry horse called Marius was renamed Sulla after it turned out to be a mare. Marius and Sulla were both Roman states''men''.

...How was there even any confusion? Stallions are extraordinarily obvious.

This troper's brother adopted a stray kitten which he assumed was female. After a visit to the vet revealed the kitten's true gender, he kept its original (fortunately, gender-neutral) name, "Token."

Was the kitten black?

This troper's pastor got a cockatoo and named her Rosita. After a DNA test revealed that the cockatoo was, in fact, male, he renamed Rosita Carlito and named his dog (for which gender is much easier to determine) Rosie.

This troper and her brother once owned two gerbils. We were told they were both female, so he named his "Kim" and mine was "Lola". Well, one day, we found a litter in the cage. We thought at first that "Lola" was the female, so we took "Kim" out. Babies died. For space reasons, we moved the two back into the cage, and...another litter. This time, my little brown was known to be the father, so "Lola" became "Lonnie" for the rest of his life.

Ray Davies would be proud.

This troper fails to grasp how gerbils can't be told apart. On the other hand, this troper has cared for over 30 gerbils.

This troper's Friend bought two male guinea pigs. A week later, they both gave birth. Then TT's friends gave two neutered male pigs to this troper. A month later, one gave birth.

this troper heard a similar story from a friend they made on IRC. this friend had been given a cat and they brought it to the vet and got it castrated. several months later it got out of the house and after a few days came back on it's own, and then a while latter the cat had a litter of kittens. it was confirmed to be the same cat (it had distinctive marks and a collar with ID), it just happened to be a hermaphrodite kitty and after the kittens were weaned they got momma kitty spayed.

This troper has three neighborhood cats who like to wander through her back yard, all assumed to be male-- named Oscar, Max (short for Maximilien) and... Brownie. Later, we found out Max's real name was 'Precious' or somesuch-- only when she had kittens and we suddenly had a bunch of little girls running around our yard looking for them. Fun times. (We didn't even get to name the kittens proper names, either. I at least really hope Maxine had the good taste to leave the yard for her romantic partners rather than embark on some truly {{squick}}ful real person pairing...

This troper has declared female by the doctor before birth. As a result most of my baby cloths had to be returned.

This troper's grandmother named one of her cats Angie because she thought it was a girl. She eventually discovered the kitten was male, but the name stuck.

This troper once received a bunch of hens from a friend. After seeing one of them drink similarly to "Fabbio"'s laugh, we named it after him. Turned out it was accurate, as we found out one noisy morning.

All that needs saying is that a stray named Hermes swiftly became Hermione after she got close enough to be cuddled and not freak out.

This troper's dad had a dog that the entire family thought was male...until it had puppies. From Duke to Dukette. And we also discovered that my hamsters were NOT two boys (although no names were changed), but then, who hasn't had that happen?

How exactly do you get a dog's gender wrong? They're not like cats who have everything inside, all you need to do is have a look while they're lying on their backs.That said, plenty of people thought my late dog was a girl but that was probably because he was very pretty for a boy.

I'm left wondering that myself about cats as they '''do not''' "have everything inside". Only monotremes, elephants, and marine mammals have that dubious privilege AFAIK. No doubt, though, that cats get very annoyed when you investigate their rear so the fear of getting horribly maimed while trying to sex one may play a part in this affair.

They're still a lot less obvious then dogs,whose gender can be determined from a distance.

I've had plenty of people assume my dog is male, probably because she's pretty big. Though I can't imagine a dog's owner not noticing a rather large set of genitals.

This troper's aunt and uncle had a cat named George, that turned out to be female. They kept the original name, which led to much confusion.

This troper's friend had a cat whose sex she didn't know, until her mom told her the cat was a male. This troper had grown up on a farm so had lots of experience with that kind of thing, and told her friend that it was a female. No one believed this troper until the cat got pregnant.

Inverted: This troper once read a story submitted to ''Cat Fancy'' magazine about a woman who adopted a calico cat and presumed it was female, as she had been told that calicos are always female. "Calico Sue" turned out to be that one-in-1,000 calico ''male'' which survives to adulthood.

Actually, male calicoes are possible, but a fertile one is not. They have XXY sex chromosomes, equivalent to a human with Klinefelter's Syndrome.

This troper's sister was once given a pet bird, who was named Max. Guess who started laying eggs.

When this troper's mom and aunts were girls, they had a cat named Prince Charming. They came home from church one day to find Prince Charming nursing a newborn kitten. To be fair, Princess was a long-haired cat, so it would have taken some detailed checking to find the truth.

Once this troper and his siblings received three kittens two light gray ones with tiger stripes and a fluffy gray and white one we thought the two tiger striped ones were male and the fluffy one was female, but after they had grown up one of the tiger striped ones had gotten pregnant by another farm cat and we soon figured out that they were the opposite genders we thought they were.

This troper acquired her first rat from a friend of her sister's who thought her pets were both male; given the, well, ''ostentation'' of male rat anatomy, how the mistake was made is a mystery.

The same thing happened to this troper when she and her siblings got a few rats. The sad thing was, it took two weeks and a four-year-old's observation to realize that 'Zombie Ed' was the only girl in the group. Never found out from the new owner if she had babies or not.

This troper acquired a pair of cockatiels from an acquaintance, and was assured that they were male and female. The "male" (originally named Speckles, but ending up with the equally-unisex name Crackers after I told my mom we couldn't keep calling it Crackbaby) started laying eggs a short time afterward. We soon attached "Miss" to her name.

This troper acquired a trio of hamsters from a pet store. They were sold to me as all female. Having raised hamsters for years, I'm a little more adept at spotting the "equipment", so I wasn't too surprised to discover that one of the females was a boy. Bear-Bear, as he was soon named, must've had the time of his life in that tank of females.

This troper acquired a pair of cockatiels and a ring-neck parakeet (which is a highly misleading name for the species) from an acquaintance of her niece. I am pretty sure the ring-neck is a girl, although the previous owners named her Tommy. I'm just waiting for the other shoe to drop on the 'tiels.

Pet stores are notoriously inept at spotting obvious signs, mainly because a good portion of employees won't sex the animals themselves unless prompted. Instead, they trust the companies that ship the animals to them. The problem with that is, a good portion of the time, the people who work for those companies don't know what to look for either. This troper (who worked at a Petco) used to regularly curse the company who shipped the mice, as they had an annoying habit of mixing up males and females. (I also would curse weekend associates for not paying attention. I came in one Monday to discover a pregnant mouse who, by the time I saw her, was at least a foot wide. How can someone miss ''that''?)

Possible InvertedTrope example: This troper took in a stray kitten late last November who was somewhere between 1-2 months old, which would make the kitten, as of today's date (May 2 2009), 5-6 months old. Priscilla (the kitten) looks and acts outwardly female, and at least ''appears'' to have the genitalia of a female cat; however, she hasn't yet gone into heat (though she has not, to our knowledge, been spayed, and appears to have been born a feral). Because of this, this troper speculates that Priscilla may in fact be male.

Give her a few months (or just take her to the vet to be fixed!). Six months is about "puberty" age in a cat, so she's probably just about to the age to start heat cycles.

This troper, when she was very young, had a cat named Larry. One day, we took Larry to the vet to get "him" neutered, and found out that Larry was a girl! We still called her "Larry" though, as it had kind of stuck before we found out her actual gender. Yep, we had a female cat named Larry.

How about a female rat named Ralph? "He" was named after the protagonist of Beverly Cleary's books ''The Mouse and the Motorcycle'' and ''Runaway Ralph''. By the time Ralph's actual gender was discovered, she'd been Ralph for so long, it didn't feel right to change her name. Neither could we think of a partial change which didn't seem hopelessly awkward: what, "Ralphina"? Noooo... (Getting a rat was a last-minute decision: after being told--relative to mice--that rats are more intelligent, personable and inclined to "get to know you." Which is true: Ralph was affectionate and displayed definite personality, preferences etc. No matter how long you've had a mouse, it'll remain skittish & inclined to relieve itself at "random" intervals but especially if you try to play with it.)

This troper's father kept a parrot he named Frank. The kicker? This was an Eclectus parrot, and it is ''very'' easy to determine their gender. Frances was red and blue.

this troper has a friend relate to them once the story of a pet cat they use to have. the pet cat was decidedly male and they brought him to the vet to get him castrated. about half a year later the cat managed to zoom out of the house as someone was leaving. the cat came back later and it definitely was the same cat as the markings were the same and it was wearing the same collar. the only thing is, the cat came back PREGNANT. turns out it was a rare fertile hermaphrodite. they get the cat spayed after the kittens were weaned and sent off to their new families.

When this troper was around six or so, she got two pet mice and asked for two girls, and she named them Jenny and Mary. Jenny got pregnant and after the pink little baby mice were born, Mary got a name change to James, since she apparently was a he (since the other mouse was the pregnant one). We actually had quite a few baby mice from those two, and oddly enough, Jenny lived the longest of all my pet mice despite being one of the first two.

This troper's uncle had a cat who he originally thought was male, so he named "him" Fred. Not too long later, Fred was revealed to be a girl. The name stuck, though my great-grandmother insisted that she be called "Freda" instead of Fred.

This troper's friend rescued a feral cat and named it Mia, brought it into the vet, only to find out Mia was a boy. She kept the name, because cats could care less what you call them anyway.

I once worked at a school biology lab where they would bring in mice for experiments. Of course as time passed we lost track of which mice were supposed to go into which cages and two pairs in particular got ''very'' friendly with each other. Jokes about lesbian mice were made...then two litters of baby mice were born. Whoops.

This feline at heart troper actually has a pet cat called Chalice that I thought was a male. Turns out he was actually a SHE. I had to rename her Diamond.

How is Chalice a masculine name? (Especially compared to Diamond, which has developed into a pretty feminine-leaning GenderBlenderName, when it is a name.)

Happened quite a lot to this troper.

When her mother and her went out to buy guppies, we picked only the males. You can tell the males by the giant, pretty tails, right? WRONG. We wound up with almost seven generations of guppy before they all died off of old age.

As far this other troper knows, guppies are able to change their gender...

A feral cat outside had kittens. No big, we got all the females spayed and that would be the end of it, right? WRONG! Barricade, a seemingly male cat, had kittens. Thre of them. (You'll be hapy to know that barricade is not spayed, and her kittens live inside untill such a time as they too are spayed.)

Don't get me started on mice.

This troper's neighboor got two Guinea Pigs from the same litter that were "definatly" both male. Cue the ten baby litter. But I guess the siblings had the "crazy" gene, because the babies ended up killing their mother.

This troper had a pair of gerbils as a teenager. I got them young, so they both looked female. One was brown, while the other was albino and obviously the runt of the litter. When the brown one's male parts developed I initially thought he was sick. Once I figured out his gender, I was initially relieved, but then I started getting nervous again about what I would do if they had pups. Then the runt developed. I kept their female names because my grandmother lived with us at the time and I did not need a quarter of my extended family to hear about my inability to sex a gerbil.

Another no-pregnancy-involved example: This troper's family occasionally fosters puppies for the Humane Society. One time, we had two little Lab mixes, who we assumed were both boys. Then, one day, when my sister and I were letting the neighbors' grandson hold them, my sister noticed something ''odd'' about one puppy's privates...

As a child, this troper was close friends with a girl who had a guinea pig named Ashley and two cats. When she acquired another kitten, she decided she had too many pets and let this troper's family take Ashley. We took Ashley to the vet to make sure all was well with our new furry friend, and they told us Ashley was in fact a male. The name stuck, because we were told that males could be named Ashley, but this was unfortunately after we had bought him a pink cage and plastic igloo.

This troper's neighbours put their young cat, Louise, on the pill to avoid unwanted pregnancy. Only two years later did they realize, while petting her, that Louise had some... sort of package down there. He's been renamed Louison, but perhaps as a consequence of taking the pill, is still only half as big as his male twin (this troper's cat).

This troper's brother's "tomcat", Casper, was renamed Cassie after it became obvious that she was pregnant. This troper also recalls spending ages trying to figure out the genders of her guinea pigs when she was young. They didn't seem to like it much, for some strange reason...

This troper got a baby turtle. She referred to it as "he". The vet declared it female, though it's hard to tell with small turtles (but it had no signs of growing the long claws of the males). Surprise, surprise, its claws grew and the turtle...flashed its owner. Needless to say, it was a he all along.

A non-domestic example: This troper was at an animal reserve-type-place in Costa Rica with a large group of other tourists. In one of the cages was a large puma, and one of the people in the group commented "Is she pregnant?" The guide replied "No, he's just fat."

This troper's cat, Spike, became a proud mother of four kittens after sixteen months of presumed maleness.

There was once an orange cat in this troper's neighborhood. I had heard that all orange cats were male, so the cat was named Alexander. Later, I discovered that the cat was, in fact, a female, and that it was just about 60% of orange cats that were male, not all of them. I now call the cat Alex.

Years ago, as little kids, this troper and her sister got pet mice. Two girls, named Cutie and Angela. My Angela was certainly female, but when I held my sister's Cutie for the first time, I noticed there was a little more parts to 'her' than what were on Angela. A month later, seven little pink baby mice were born. Unfortunatley Angela was eaten by the cat. Half of the baby mice were killed by Cutis, and the rest died shortly after. Hopefully, my recent mice will fare much better, two females, Riza and Rebecca, one of whom (Riza) was impregnated while at the pet store.

Was Riza's mate named Roy, by any chance?

This Troper's mother grew up with Brutus, who retained the same name even after producing kittens. And this troper's aunt had an inverted version - she keeps hens, and at one point named a chick before it got big enough to tell what sex it was. The poor thing was eaten by a fox in the end. RIP, Petal the Gender-Confused Rooster.

This troper didn't find out one of his cats was female from an unforeseen pregnancy, but rather when he took the cat to be fixed. The breeder had promised a male kitten... Strangely enough, it was an orange tabby, too...

A long time ago This Troper got a pet mouse. Her Biology teacher said the mouse was male. Her friend decided the mouse needed some company and gave this Troper another male mouse. Soon after that the first mouse got pregnant. When the baby mice were old enough, this Troper decided to give them (and their father) away to a pet store, except for one female mouse to keep the first mouse company. The guy at the shop picked a 'female' mouse for this Troper. After a while mommy mouse had some more babies.

This troper's mother had a lovebird named Peaches. The guy at the pet store had assured her that this bird was absolutely female. Fast forward to a few years later, when this troper helped move Peaches into the same cage as a female cockatiel named Topper. One day, while this troper was in the bathroom, she heard strange noises coming from the birdcage. THOSE kind of noises. Not too long after, the cockatiel laid a clutch of eggs and the one egg that did hatch had a rather interesting little hybrid birdie that looked like a cross between a lovebird and a cockatiel. Turns out Peaches was Mr. Peaches.

We once took in what we thought was a stray pregnant cat, and kept it in our house for a few days cause we thought it was damn close to having kittens. Well a few lamppost Missing posters soon disposed all those assumptions, turns out it was just a really fat neutered male. It was around this same time we learned, that we sucked at telling hamsters gender, cause the one hamster my sister got from a friend turned out to be already pregnant, and we thought we had separated the kids by gender after they got old enough, well one more litter after, we learned different. Also, fun fact, hamsters can get pregnant again a few hours after giving birth...seems we didn't get those two into separate cages fast enough.

This troper's sister, a vet, once had to neuter AND spay a cat that turned out to be a hermaphrodite. I forget which gender the owner thought it was originally.

At my cat's first checkup (well, one cat out of five), the vet gave the news rather humorously: "Oops, Stella's a Stanley!"

One of the most bizarre examples I've ever experienced...upon finding a stray, fluffy, black cat at the end of our road (we did not look back there, initially, and even when we did it was a LOT of fur), we had decided that it was a female and so I nicknamed it "Saaski". When he was handled and cuddled more, I accidentally shifted my hand under his tail, and in a stunning moment blurted out "This is no female! Feel the pom-poms on this boy!" ...Saaski, now renamed Charlie Murphy, was just fine. Until he started having bladder problems, that is. Now, he's neutered, and essentially got the cat equivalent of a sex change to fix his urethra (No. Really.). Is it possible for a cat to even get gender confusion?

Happened to this troper with her first pet cat, who was named Jinx (fortunately, a rather gender-neutral name). It took a vet to tell her family that their beloved little 'girl' was actually a little boy.

this troper once got a kitten that she named Jimmy; turns out it was a Jenny, and we got another generation of kittens (not that I was complaining)

Played straight with my sister's cats and my friend's rabbits, subverted by my rabbits.

Sister: brought a cat we dubbed "Bell", as we were all fairly certain it was a she. As Bell was lonely, she also bought another cat named Muffin, again, we were all fairly certain muffin was a girl...thenn muffin got pregnant...

Friend: A friend of mine told me the story how she walked out of the pet shop with 2 "Brothers", and ended up with 6 little bunnies. And got a lifetime supply of rabbit food out of it.

Me: My rabbits are most definatly male, brother's, and have lived together for five years, the last two under my care. Doesn't stop the bigger one from permanently mounting his brother though.

This troper obtained, from a rescue agency, two 10-week-old kittens that were listed as sisters. I named them Catherine and Grissom, figuring that "Grissom" was gender-neutral. At their first vet visit a week later, the vet broke the news that the kittens weren't sisters, they were actually brothers. I decided that changing Catherine's name would be more trouble than it was worth, and after three years, I now have a hard time not seeing "Catherine" as gender-neutral, too.

When this troper and her friend were 10 and 11 years old, we caught a spider with a leg span of about four inches. Being fascinated by all things creepy and gross, we kept it in a little plastic fish tank and lovingly named 'him' Aragog. Four months after finding our little tarantula-wannabe, 'he' had babies. Thousands of babies. We promptly renamed her Shelob, but then we had to let her go.

This troper got two hamsters when he was about 7 or 8; a large aggressive brown one we named Bernard and a white calm, peaceful one we named Bianca, after TheRescuers. Needless to say, they would fight a lot, and Bianca died a few weeks later. My whole family was crushed, until we saw "Bernard" kept getting fatter no matter how much or how little "he" ate, until a couple weeks later...yeah. We sold most of the babies to a local pet store, we kept one which we named Junior. Oh, and we never changed Bernard's name, though we did sometimes call her Bernandina afterwards...

This troper had the inverse happen on two separate occasions. There was no pregnancy involved, however.

We found an abandoned kitten in a cornfield and named her Siam, since she had blue eyes. Then, when the vet came out to do a check up on our alpaca herd, she informed that Siam was a boy. He was then renamed Sam and is one of the sweetest cats you'll ever meet.

Then, about a year later, we found another kitten in our rosebush, named her Isabel, and the process repeated. We changed his name to Seb (taking the middle syllable of Isabel), and he too is a very affectionate cat. He and Sam are the best of friends.

Many years ago, close to a decade, this troper received a pet cat from his aunt for his birthday that he named "Ash" because he assumed it was male. A few months later, he realized that "Ash" was in fact a girl when she got pregnant.

A few months ago a stray calico wandered over to our neighbors' house. The neighbors named it Kit-Kat, and when they asked us what the gender was we were confident that it was male since it had the appropriate parts, even though it is stated that calico cats are ''always'' female, no exceptions. A few weeks later we get a phone call stating that Kit-Kat was pregnant. This sent this troper and her sister into stuttering messes because it ''couldn't be possible''. Sure enough, in just a few days a very content mama cat was laying down with her three kittens and we just accepted that 'he' was a female, even though it still had BALLS.

This troper and her brother used to rescue turtles from the side of the road as children, and kept them as pets. After a while, this troper noticed a bunch of "funny white balls" in the aquarium and only realized they were eggs after accidentally smashing them. Suffice to say, after that we realized that Leonardo was a girl. And on a non-pregnancy related note, this troper has a female cat named "Tobi" (short for Tobias). The reason? When adopting the kitten, we were told that she was a he and didn't double-check until we were home and the name had already been added to the vet forms. The cat doesn't seem to mind, but does believe she's a dog.

This troper's family owns a pair of Bronze Mannikin finches, Fig and Ginger. We assumed they were both male, since the pet store informed us that all birds for sale were male. Of course, several months later, one starts sitting at the bottom of the cage and fluffing his feathers, which is standard sick bird behavior. The next morning, there's a small white egg. We still call them Fig and Ginger, but calling them girls instead of boys is tricky to remember since we're all so used to it.

This Troper had a Mickey Mouse Platy with one fin named Debbie. Debbie turned out to be a guy. We didn't change his name.

a friend of mine had gotten himself a kitten a year or two ago and called "her" Lilli, because the breeder told him it was male. When he brought her to the vet, he claimed that "Lilly" was male, so my friend decided to rename ''him'' into "Tim". Then Tim ran away. He came back soon, but my friend was a bit worried, so he brought him to the vet again, who apologized for about five times, because he figured out Tim was female after all. So Tim became Lilli again. Until Tim hit puberty and started going after the neighbours cat...

This troper, about a month and a half ago (January 2011) got a third female guinea pig as a friend for his other two females. He came home about a month and half later to find that a miniature version of the new guinea pig had miraculously appeared in the cage.

This troper, has not exactly experienced this first-hand, but she knows a song for your poor sick kitty.

No pregnancy involved, but when this troper was looking to adopt a kitten, he saw a pair of siblings, one orange and one black. The sign mentioned the girl was very good at tolerating her energetic brother, which was good, since this troper's roommate had a rambunctious kitten. He poked and played with the black kitten through the cage bars, since the orange one must have been the boy (orange coats are very common on male cats and almost unheard of on females), but when he asked to adopt her, the helper took the orange one out to his surprise. Later, when taking her to the vet, the vet initially assumed she was a boy until she read the chart.

This troper had a cockatiel that she got from a family friend, and we all thought it was a baby boy at first. Then the bird started making a bunch of squawking/laughing noises. We didn't know that those sounds were the mating call of a female cockatiel. Then the cockatiel(which had a gender-neutral name of Twinkles) started getting really aggressive and bitey. One day, while I was doing my homework, I heard my mum saying, "Well now I know why you were acting so weird - you laid an egg!" and I looked inside Twinkle's cage... sure enough, she was protecting an infertile egg in the corner. She laid seven eggs within three weeks!

My sister's roommate first found out her cat was female when she took it to a vet to get neutered. Thankfully the two cats in the house that actually ''are'' male were neutered already, and it had a gender neutral name to begin with.

This was quite common when this troper was a kid, though it was actually our vet that kept telling us our female cats were boys. It was entirely our fault when we got confused with a kitten we got more recently, we correctly thought the kitten was male, until our obviously male cat became veeery intrested in 'her', only to discover that he really was a boy when he got even older.

This actually happened with this troper's gender. The doctors said the utrasounds showed her and her twin to be male, despite this fact her aunty insisted there would be a girl. Cue smug aunt when I was a girl.