Testicular feminization or Androgen insensitivity syndrome (AIS) is inherited as an X-linked recessive, caused by a mutation in a gene coding for the androgen (testosterone) receptor, in which genetical (XY) males develop female secondary sexual characters. When a person who is genetically male (has one X and one Y chromosome) is resistant to male hormones called androgens. As a result, the person has some or all of the physical characteristics of a woman, despite having the genetic makeup of a man.