Annalee Newitz

Humans have continued to evolve quite a lot over the past ten thousand years, and certainly over 100 thousand. Sure, our biology affects our behavior. But it's unlikely that humans' early evolution is deeply relevant to contemporary psychological questions about dating or the willpower to complete a dissertation.

When it comes to the population explosion, there are two questions on the table. One, is our population growth going to kill us all? And two, is there any ethical way to prevent that from happening?

A series of studies in the 1990s and 2000s revealed that as women gained more access to education, jobs, and birth control, they had fewer children. As a result, developed countries in western Europe, Japan, and the Americas were seeing zero or negative population growth.