Definitions of intersex

Various criteria have been offered for the definition of intersex, including ambiguous genitalia, atypical genitalia, and differential sexual development. Ambiguous genitalia occurs in roughly 0.05% of all births, usually caused by masculinization or feminization during pregnancy, these conditions range from full androgen insensitivity syndrome to ovotesticular syndrome.

1.7% of people are born with a disorder of sexual development (DSD) as defined by the DSD consortium, such as those with Klinefelter's syndrome. The DSD was specifically made to be as inclusive to all atypical sexual development; not all conditions within the DSD cause sexual ambiguity or affect individuals to the same extent. In other estimates, Definitions are limited to ambiguous conditions in which typical chromosomal categorization patterns is inconsistent with phenotypic sex, or in which the phenotype is not easily classifiable as either male or female," with the prevalence of about 0.018%.

Most intersex activism is based around the end of unnecessary medical interventions on intersex youth which attempt to assign an arbitrary gender binary, often causing physical harm with no input from the child. Intersex conditions are usually expanded to include the DSD more generally, including conditions without sexual ambiguity. 0.05% of births are medically treated or considered to have ambiguous genitalia.