Androgen Insensitivity Syndrome (AIS) is a human disorder in which an individual's genetic sex (genotype) differs from that individual's observable secondary sex characteristics (phenotypes). A fetus with AIS is genetically male with a 46,XY genotype. The term 46,XY refers to the chromosomes found in most cells of the fetus. Most cells have a total of 46 autosomes, or non-sex chromosomes, and a pair sex chromosomes, XX for genetic females, or XY for genetic males. Due to a defect on the androgen receptor gene (AR) located on the X chromosome, a fetus with AIS cannot process male sex hormones or androgens. The effect on the fetus is that, compared to genetically male fetuses without AIS, it doesn't develop normal male phenotypes. The resistance to androgens affects all of the fetus's organs during embryonic development and during puberty. Although genetically male, persons with AIS can be socially raised as either female or male (sex-of-rearing) yet identify with a gender discordant with their sex-of rearing. AIS and other states of intersexuality challenge physicians, scientists, and society to evaluate definitions of sex.