Hands-on fathers typically see about a 25% testosterone drop, researcher says

Saxbe says longitudinal studies, including work in the Philippines, show men’s testosterone typically drops by roughly a quarter when they become hands-on fathers, addressing earlier questions about whether lower-testosterone men simply self-select into parenthood. She also says her lab found higher post-birth testosterone in fathers was associated with partners reporting more relationship dissatisfaction and more intimate partner aggression, while very low testosterone was linked with higher paternal postpartum depression symptoms.