Androgen insensitivity syndrome (AIS) is a difference in sex development involving hormonal resistance due to androgen receptor dysfunction.
Complete androgen insensitivity syndrome (CAIS) is an AIS condition that results in the complete inability of the cell to respond to androgens.
The unresponsiveness of the cell to the presence of androgenic hormones prevents the masculinization of male genitalia in the developing fetus, as well as the development of male secondary sexual characteristics at puberty, but does allow female genital and sexual development in those with the condition.
Individuals affected by CAIS develop a normal external female habitus, despite the presence of a Y chromosome, but internally, they will lack a uterus, and the vaginal cavity will be shallow, while the gonads, having been turned into testicles rather than ovaries in the earlier separate process also triggered by their Y chromosome, will remain undescended in the place where the ovaries would have been.
Most individuals with CAIS are raised as females.They are born phenotypically female and are usually heterosexual with a female gender identity; however, at least two case studies have reported male gender identity in individuals with CAIS.