Gently lift the kitten’s tail
Look at the shape and spacing of the openings
Female kittens usually have a vertical slit close to the anus
Male kittens usually have a round opening farther from the anus
Female kittens often look like an exclamation mark
Male kittens often look like a colon
Check for any small testicle bulges in older kittens
Compare with a known male and female kitten if possible
Handle the kitten gently and briefly
Ask a veterinarian if you are unsure