It is important to recognize the different diagnoses that can be associated with intersexuality so that one can help patients find answers about their bodies. It is also important to note that not everyone has a diagnosis and that, in many cases of intersexuality, the cause is unknown. The range of genital morphology is also large and has not been well described. Secondary sexual characteristics may also vary between individuals and between people from different ethnic backgrounds. For example, most people will agree that breast size and shape can be vastly different from one person to another and at different stages of the life cycle. Some men may have larger breasts than some women. Some women will also have more facial and body hair than some men.
The following are just a few of the most common syndromes associated with intersexuality.
Androgen Insensitivity Syndrome (AIS)
These are people with an XY karyotype who have mutations in their androgen receptor gene causing insensitivity to androgens. In the case of complete AIS, they are phenotypically female. Individuals with partial AIS may have a spectrum of female sex characteristics. Most have undescended testes that are usually removed because of the increased risk of cancer. At puberty they develop breasts but do not menstruate and develop little hair.
5-Alpha Reductase Deficiency
This mutation affects people with an XY karyotype. Before puberty, these individuals are phenotypically female or their sex may be intersexed. At puberty they begin to develop male secondary sex characteristics and their phallus enlarges and begins to act more like a penis. People with an XX karyotype that have this mutation are phenotypically unambiguous females with normal fertility.
Congenital Adrenal Hyperplasia
This syndrome can occur in both genetically male and female children. However, because of excess androgen production, the genetically female children undergo virilization that results in different degrees of intersexed genitals. This is the most common cause of ambiguous genitalia.
These are people with an XXY karyotype that may also demonstrate some genital intersexuality.