The Myth of the Toddler Testosterone Surge

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Most parents of boys have had this experience— their son shows some kind of challenging behavior and someone nearby shrugs and says something along the lines of “boys will be boys,” or otherwise implies that rough or rowdy behavior is natural and even inevitable for boys. Although meant to be validating, these remarks suggest that nothing that can— or should— be done to change or improve the behavior and parents must simply accept it. To further drive home this point, there is now a viral sound bite circulating on social media stating that boys between the ages of three and five experience a surge of testosterone comparable to that of puberty—supposedly explaining why boys are more active, defiant, or aggressive during these years. But is it true that boys experience a testosterone surge during the early childhood years and what does the science say about how parents should manage the behaviors of boys?

The Research on Testosterone

Despite how widespread this idea has become, research consistently finds that testosterone does not show any significant increases during this time. Testosterone does increase during the first two trimesters of pregnancy and during the first six months of a boy’s life (a time period referred to as mini-puberty). The rise in testosterone during pregnancy and infancy may contribute to behavioral differences between boys and girls later in life but it is certainly not the only factor that drives these behavioral differences. For example, research finds that infants with higher testosterone levels show more stereotypical male play as toddlers (such as playing with trains instead of baby dolls) yet