Adrienne LaFrance researches the neurological changes that women undergo when they become mothers. Yes, it’s like a drug:
“We see changes at both the hormonal and brain levels,” brain researcher Ruth Feldman told me in an email. “Maternal oxytocin levels—the system responsible for maternal-infant bonding across all mammalian species—dramatically increase during pregnancy and the postpartum [period] and the more mother is involved in childcare, the greater the increase in oxytocin.” Oxytocin also increases as women look at their babies, or hear their babies’ coos and cries, or snuggle with their babies. An increase in oxytocin during breastfeeding may help explain why researchers have found that breastfeeding mothers are more sensitive to the sound of their babies’ cries than non-breastfeeding mothers. … What scientists do know, Feldman says, is that becoming a parent looks—at least in the brain—a lot like falling in love.
Dads get doped up too, but in a different way:
Oxytocin does not seem to drive nurturing behavior in men the way it does in women, Feldman and other researchers found in a study last year. Instead, a man’s parental brain is supported by a socio-cognitive network that develops in the brain of both sexes later in life, whereas women appear to have evolved to have a “brain-hormone-behavior constellation” that’s automatically primed for mothering. Another way to look at it: the blueprint for mothering behavior exists in the brain even before a woman has children.