Lift the kitten’s tail gently
Look at the shape and spacing of the openings
Male kittens usually have two openings farther apart
Female kittens usually have two openings closer together
Male kittens often have a round genital opening
Female kittens often have a vertical slit-shaped genital opening
Male kittens may have a small gap that looks like a colon
Female kittens may have a gap that looks like an exclamation mark
Check for a scrotal area in males as they grow older
Compare with a known male and female kitten if available
Ask a veterinarian if you are unsure