Telling the sex of a kitten is not easy, especially when they are tiny! So since Kim, our receptionist, had a litter of 4 week old kittens handy, I thought I’d take the opportunity to show you what to look for. Let me just say, I got a lot of flak for taking pictures of kitten butts (and I took a LOT because the camera would not focus on their squirmy back sides!). But if it helps a few people out there it will be worth it!
The biggest thing to look for is the distance between the anus and genitalia, as well as the shape of the opening of the genitalia. On a boy, there is a greater distance between the two, and the opening of the prepuce is a circle:
On a girl, there is less space between the two openings, and the vulva has a vertical slit for an opening:
I know it can be hard to see things on a picture, so I drew a diagram as well. The dotted line outlines the perineal area (has thinner hair).
Other clues include coat color. Tri-colored cats are nearly always female. The genetic code for coat coloring is on the sex chromosomes, and you must have two X-chromosomes to get three coat colors. A male tri-colored cat is very rare, because it must have an XXY genotype instead of the normal XY. Orange colored cats tend to be male, but not always. When in doubt, ask your vet!
