Viewing the rabbit's genitals is how a bunny owner can tell if the rabbit is a male or female. Lifting the bunny's tail and manipulating the genital area is the most effective way to determine a rabbit's sex. The genitals are located near the anus, which is right under the tail.
Gently pressing on the area on either side of the opening below the anus will make the genitals pop out. Male rabbits have a penis or a shaft with an open end. Male rabbits will also have noticeable testicles appear between 9 and 20 weeks of age, which should be present unless the rabbit has been fixed. Female rabbits will have a vaginal opening become visible, and there aren't any testicles in the area.