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.

Geneticists have a better understanding of how prehistoric pairings unfolded, with new research suggesting they were mostly between male Neanderthals and female humans.

A University of Michigan-led study based on a review of genetic and health information from more than 276,000 people finds strong support for a decades-old evolutionary theory that sought to explain ...