Sometimes, in some of the species we treat, sex can be harder to determine than in other species where it is straightforward, like dogs. This can lead to some interesting situations. Just yesterday, I had a client call and say she needed to bring her young male guinea pig in right away. She was concerned that he might have bloat or a tumor as his belly was large and poking out. When he arrived, it was fairly apparent that "he" was pregnant. A quick check of the genitals revealed that indeed, "he" was a "she" and an x-ray revealed multiple (5-6) little skeletons in her belly. I was thrilled there was nothing wrong and went to break the news to the soon-to-be grandma.
That is just one example, but there have also been many cats believed to be one sex as kittens, but when they get a little bigger, we find out they are the opposite. It is always a bit awkward when the cats come in with very masculine or feminine names and then I must tell the owner that their cat has been mis-sexed. It is common, however. There is a saying in vet med that if you've never tried to spay a male cat, you haven't been practicing long enough. I can say, going into my 16th year of practice, I have yet to accidentally try to spay a male cat, but just writing this sentence will likely jinx me. Check back with me in a few weeks.
I said in the beginning that dogs are straightforward as far as sexing. Well, I'll leave you today with my favorite mistaken sex story. One day I was doing a healthy puppy exam on a little lab/terrier mix puppy that was clearly a normal little male dog. I kept referring to "he", "him", and "his" while talking to the owner and could sense the owner's growing displeasure. Finally, I asked if she had any questions. She told me that she did not, but she was quite unhappy because I had repeatedly referred to her new dog as a boy when it was in fact a girl. I apologized, but said, "No ma'am, your puppy is a male". Clearly agitated she argued with me that the dog was a female, that was what she had purchased from the breeder, and that I should know better. Since the dog was on the table between us, I picked it up and showed her the dog's prepuce and told her that was the covering over his penis. He was clearly a male. She told me that was "where she tinkles from" (she was not wrong there) and would be finding a new vet. Oh, how I wish I were a fly on the wall at her next vet visit...