Hormones, context, and Brain Gender: A review of evidence from congenital adrenal hyperplasia

Brain organization theory suggests that steroid hormones during fetal development permanently organize the brain for gender, including patterns of sexuality, cognition, temperament, and interests that differ by sex. This widely-accepted theory has important implications for health, ranging from medical management of infants with intersex conditions to suggested etiologies for sex differences in autism, depression, and other mental health problems. Studies of genetic females with congenital adrenal hyperplasia (CAH), in which high prenatal androgens have been linked to both atypical genitals and masculine patterns of gender and sexuality, are particularly important. Based on a comprehensive review of research on CAH, this article demonstrates that such studies have neglected four broad categories of variables that plausibly affect psychosexual development: 1) physiological effects of CAH, including complex disruption of steroid hormones from early development onwards; 2) intensive medical intervention and surveillance, which many women with CAH describe as traumatic; 3) direct effects of genital morphology on sexuality (versus indirect effects that masculine genitals may have on gender socialization); and 4) expectations of masculinization that likely affect both the development and evaluation of gender and sexuality in CAH. Complex and iterative interactions among postnatal biological variables, medical interventions, and social context provide a more plausible explanation for atypicalities in psychology and behavior that have been reported for genetic females with CAH than the conventional explanation that early androgens have masculinized their brains. (C) 2011 Elsevier Ltd. All rights reserved.