The appearance of XX<unk> s can fall into one of three categories: 1)<unk> s that have normal internal and external genitalia, 2)<unk> s with external ambiguities, and 3)<unk> s that have both internal and external genital ambiguities (also known as true hermaphrodites). External genital ambiguities can include hypospadias, micropenis, and clitoromegaly. Typically, the appearance of XX<unk> s differs from that of an XY<unk>  in that they are smaller in height and weight. Most XX<unk> s have small testes, and have an increase in maldescended testicles compared to XY<unk> s. Many are sterile. Some XX<unk>  individuals have decreased amounts of body hair and decreased libido. Individuals with this condition sometimes have feminine characteristics, with varying degrees of gynecomastia but with no intra-abdominal Müllerian tissue. According to research at the University of Oklahoma health science centers, despite XX<unk> s exhibiting feminine characteristics, their behaviours are usually representative of masculinity in their culture. They generally have small testes and may also have abnormalities such as undescended testes (cryptorchidism) or the urethra opening on the underside of the penis (hypospadias). A small number of affected people have external genitalia that do not look clearly<unk>  or clearly female (ambiguous genitalia). Affected children are typically raised as<unk> s and are likely to have a<unk>  gender identity. Masculinization Schematic of sexual differentiation in humans The degree to which individuals with<unk>  develop the<unk>  phenotype is variable, even among SRY-positive individuals. A completely<unk>  phenotype usually develops in the presence of the SRY gene but, in some cases, the presence of the SRY gene can result in internal and/or external genitalia ambiguities. Normal XX females undergo X inactivation during which one copy of the X chromosome is silenced. It is thought that X inactivation in XX<unk> s may account for the genital ambiguities and incomplete masculinization seen in SRY-positive XX<unk> s. The X chromosome with the SRY gene is preferentially chosen to be the active X chromosome 90% of the time, which explains complete<unk>  phenotype being observed often in SRY-positive XX<unk> s. In the remaining 10%, X inactivation spreads to include a portion of the SRY gene, resulting in incomplete masculinization. Masculinization of SRY-negative XX<unk> s is dependent upon which genes have mutations and at what point in development these mutations occur.
XX male syndrome
XYY syndrome
XXXY syndrome
XYYY syndrome
XXYY syndrome
XXXXY syndrome
Turner syndrome
XYYYY syndrome