Humans don’t have a defined mating season like deer or wolves. Here’s how evolution blended biology, culture and social life into year-round intimacy.

An Asian water dragon hatched from an egg at the Smithsonian National Zoo, and her keepers were shocked. Why? Her mother had never been with a male water dragon. Through genetic testing, zoo ...

This story is part of a week-long series on reproduction, from prenatal testing to childfree Reddit. Reproduction is messy. The genetic swaps and recombinations that occur when gametes merge don't ...