Androgens and the Evolution of Male-Gender Identity among Male Pseudohermaphrodites with 5α-Reductase Deficiency

TLDR

These male pseudohermaphrodites have high‑normal testosterone levels, respond well to testosterone, and serve as unique models for studying testosterone’s role in gender identity compared to female upbringing. The study aimed to determine how androgens influence male‑gender identity by examining male pseudohermaphrodites with 5α‑reductase deficiency. The authors examined individuals with 5α‑reductase deficiency, born with female‑appearing genitalia and raised as girls, to assess androgen effects. Among 38 subjects raised as girls, 17 of 18 adopted a male gender identity and 16 of 18 a male gender role during or after puberty, indicating that normal testosterone exposure in utero, neonatally, and at puberty substantially shapes male‑gender identity, overriding female rearing.

Abstract

To determine the contribution of androgens to the formation of male-gender identity, we studied male pseudohermaphrodites who had decreased dihydrotestosterone production due to 5 alpha-reductase deficiency. These subjects were born with female-appearing external genitalia and were raised as girls. They have plasma testosterone levels in the high normal range, show an excellent response to testosterone and are unique models for evaluating the effect of testosterone, as compared with a female upbringing, in determining gender identity. Eighteen of 38 affected subjects were unambiguously raised as girls, yet during or after puberty, 17 of 18 changed to a male-gender identity and 16 of 18 to a male-gender role. Thus, exposure of the brain to normal levels of testosterone in utero, neonatally and at puberty appears to contribute substantially to the formation of male-gender identity. These subjects demonstrate that in the absence of sociocultural factors that could interrupt the natural sequence of events, the effect of testosterone predominates, over-riding the effect of rearing as girls.