This pioneering study looks at the effects of prenatal testosterone on postnatal development and behavior. Hormonal effects on behavior have long been studied in animals; the unique contribution of this book is to suggest a connection between human fetal hormones and later behavior. It details for the first time testosterone's effect on social and language development, opening a new avenue of research for cognitive neuroscience.

The authors look at samples of amniotic fluid taken during amniocentesis at 16 weeks' gestation, and relate the fetal level of testosterone (which is present...