The early postnatal period, mini-puberty, provides a window on the role of testosterone in human neurobehavioural development

Graphical abstract The early postnatal period of testicular activation may provide an accessible window for studying the role of early testosterone exposure in human gender development. There are two periods during early human development when testosterone is higher in developing males than females. These periods occur from about week 8 to 24 of gestation and from about the first to the sixth month postnatal. Both of these periods occur during times of rapid brain development. It is well-established that testosterone during the first of these periods influences later gendered behaviour, including gender-typical play, sexual orientation, and gender identity. There is recent evidence suggesting that testosterone during mini-puberty, just after birth, also influences gendered behaviour, particularly gender-typical play. This early postnatal period when testosterone is elevated is more accessible than the prenatal period, and so could provide a valuable opportunity for studying the role of testosterone in human neurobehavioural development.