Newborn rats (pups) cannot urinate or defecate on their own until the mother elicits a spinal reflex by licking the anogenital region on each pup. However, the mother spends more time with the male pups. They use their scent of smell to distinguish androgen metabolites in the urine of pups. The stimulation masculinizes the spinal cord to allow more SNB cells to survive after birth. Females who are licked frequently, however, have increased estrogen and oxytocin sensitive in maternal associated brain regions making them more attentive mothers.