Gently lift the kitten’s tail
Look for the distance between the anus and the genital opening
A male kitten usually has a larger gap between the openings
A female kitten usually has a smaller gap between the openings
A male kitten’s genital opening often looks round
A female kitten’s genital opening often looks like a vertical slit
A male kitten may have two small bulges where the testicles will develop
Compare the shape to a colon for males and an exclamation mark for females
Check again when the kitten is a few weeks older if it is hard to tell
Ask a veterinarian if you are unsure