Many may be familiar with professional athlete Caster Semenya (who has a different intersex condition), whose case was cruelly, and unscientifically, mishandled by the International Association of Athletics Federations. CAIS is one of several intersex conditions that enable people labeled female to produce levels of testosterone closer to the typical male range. But because their cells do not respond to androgen, people with CAIS also have breasts and female genitalia they are generally assigned female at birth, are raised as girls and tend to identify as such. (All people - along with frogs, fish, birds, reptiles and mammals - produce testosterone those who are categorized as male tend to produce more, on average.) Thus, on the basis of chromosomes, gonads and hormones, people with CAIS would be labeled male. These individuals have XY chromosomes, testes and levels of testosterone in the typical male range. To use a human example, drawing from a bioethics discussion about sex assignments in professional sports, some people are born with a condition called complete androgen insensitivity syndrome (CAIS).