Androgen insensitivity syndrome

Androgen insensitivity syndrome is a condition that affects sexual development before birth and during puberty. People with this condition have one X chromosome and one Y chromosome in each cell. In people with androgen insensitivity syndrome, the body's cells and tissues are unable to respond to certain male sex hormones (called androgens) that are important for normal male sexual development before birth and during puberty. As a result, affected individuals may have external sex characteristics that are typical for females or have features of both male and female sexual development.

There are three forms of androgen insensitivity syndrome: complete, partial, and mild.

Complete androgen insensitivity syndrome occurs when the body does not respond to androgens at all. People with this form of the condition have external sex characteristics that are typical of females. Affected individuals do not have a uterus. They have male internal sex organs (testes) that are undescended, which means they are located in the pelvis or abdomen instead of outside the body. As such, affected individuals do not menstruate and are unable to conceive a child (infertile). People with complete androgen insensitivity syndrome also have sparse or absent hair in the pubic area and under the arms.

The partial and mild forms of androgen insensitivity syndrome occur when the body's tissues are partially sensitive to the effects of androgens. 

People with partial androgen insensitivity can have genitalia that look typical for females, genitalia that have both male and female characteristics, or genitalia that look typical for males.  

People with mild androgen insensitivity are born with male-typical sex characteristics, but they are often infertile and tend to experience breast enlargement at puberty.