In addition to the male and female sexes, Fausto-Sterling proposes adding three other categories including herm, (a true hermaphrodite) who has both testes and ovaries, merm (a pseudohermaphrodite male), who has testes and no ovaries , although some aspects of the female genitalia, and fem, (a pseudo-hermaphrodite female) who has ovaries and some aspects of the male genitalia but no testes. The reason for adding these genders is to be more accurate and inclusive of all people. Fausto-Sterling's arguments for having at least five sex categories are valid because having only two categories is biologically inaccurate and exclusive to people who do not fit neatly into either category, both contributing to social development.