Androgen insensitivity syndrome (AIS) is a difference in sex development involving hormonal resistance due to androgen receptor dysfunction.It affects 1 in 20,000 to 64,000 XY (karyotypically male) births. The condition results in the partial or complete inability of cells to respond to androgens. This unresponsiveness can impair or prevent the development of male genitals, as well as impairing or preventing the development of male secondary sexual characteristics at puberty. It does not significantly impair female genital or sexual development. The insensitivity to androgens is therefore clinically significant only when it occurs in genetic males, (i.e. individuals with a Y-chromosome, or more specifically, an SRY gene). Clinical phenotypes in these individuals range from a typical male habitus with mild spermatogenic defect or reduced secondary terminal hair, to a full female habitus, despite the presence of a Y-chromosome.AIS is divided into three categories that are differentiated by the degree of genital masculinization: complete androgen insensitivity syndrome (CAIS) is indicated when the external genitalia are those of a typical female; mild androgen insensitivity syndrome (MAIS) is indicated when the external genitalia are those of a typical male, and partial androgen insensitivity syndrome (PAIS) is indicated when the external genitalia are partially, but not fully, masculinized. Androgen insensitivity syndrome is the largest single entity that leads to 46,XY undermasculinized genitalia.Management of AIS is currently limited to symptomatic management; no method is currently available to correct the malfunctioning androgen receptor proteins produced by AR gene mutations.
Likewise, the androgen receptor itself is generally inactive in the cell until androgen binding occurs.The following series of steps illustrates how androgens and the androgen receptor work together to produce androgenic effects:

In this way, androgens bound to androgen receptors regulate the expression of target genes, thus produce androgenic effects.Theoretically, certain mutant androgen receptors can function without androgens; in vitro studies have demonstrated that a mutant androgen receptor protein can induce transcription in the absence of androgen if its steroid binding domain is deleted. Conversely, the steroid-binding domain may act to repress the AR transactivation domain, perhaps due to the ARs unliganded conformation. Androgens in fetal development
Human embryos develop similarly for the first six weeks, regardless of genetic sex (46,XX or 46,XY karyotype); the only way to tell the difference between 46,XX or 46,XY embryos during this time period is to look for Barr bodies or a Y chromosome. The gonads begin as bulges of tissue called the genital ridges at the back of the abdominal cavity, near the midline. By the fifth week, the genital ridges differentiate into an outer cortex and an inner medulla, and are called indifferent gonads. By the sixth week, the indifferent gonads begin to differentiate according to genetic sex. If the karyotype is 46,XY, testes develop due to the influence of the Y chromosome’s SRY gene.