Hormone-dependent adolescent organization of socio-sexual behaviors in mammals

• Gonadal hormones organize sociosexual behaviors during adolescence.
• Sexual behavior and aggression are organized in males.
• Behaviors related to energy balance and maternal care are organized in females.
• Mechanisms include synaptic rearrangement and the addition of new neurons and glia.

The adolescent transition from childhood to adulthood requires both reproductive and behavioral maturation as individuals acquire the ability to procreate. Gonadal steroid hormones are key players in the maturation of behaviors required for reproductive success. Beyond activating behavior in adulthood, testicular and ovarian hormones organize the adolescent brain and program adult-typical and sex-typical expression of sociosexual behaviors. Testicular hormones organize sexual and agonistic behaviors, including social proficiency — the ability to adapt behavior as a function of social experience. Ovarian hormones organize behaviors related to energy balance and maternal care. These sex differences in the behaviors that are programmed by gonadal hormones during adolescence suggest that evolution has selected for hormone-dependent sex-specific organization of behaviors that optimize reproductive fitness.