Hormones and neuroplasticity: A lifetime of adaptive responses

•Hormones confer neuroplasticity during life stage transitions in males and females.•Sex steroid hormones modulate social recognition behavior in males and females.•Gonadal steroid hormones influence paternal behavior and structural plasticity.•Peripartum fluctuations in steroid hormones alter the brain and behavior in females.•Previous parity reduces hormone levels, brain aging and alters disease risk.