How to tell if a kitten is male or female

Almost all (but not ALL) kittens of calico (black, white and orange) or tortoiseshell (black and orange) are females. The opening just below the tail is the anus. A male has a much greater distance between the genitals and anus than females, which are ½ inch apart for a male kitten or more than 1 inch apart for a male adult cat. In kittens of similar size, the distance between the anus and the genital opening is greater in the male than in the female.

A female kitten’s genitals are closer to the anus and look like a straight line or a tear.

References:

• How to tell the sex of a kitten | International Cat Care
• Determining gender (sex) of a kitten | Veterinary Teaching Hospital | Washington State University