Men seek youth and beauty, while women focus on wealth and status — evolutionary psychologists have long claimed that these general preferences in human mating are universal and based on biology. But new research suggests that they may in fact be malleable: as men and women achieve financial equality, in terms of earning power and economic freedom, these mate-seeking preferences by gender tend to wane.

The idea behind the evolutionary theory is simple: biologically, sperm are cheap — men make 1,500 sperm per second on average. In contrast, eggs are expensive; typically, women release just one egg a month and each baby girl is born with her full lifetime’s supply of egg cells. (Yes, this means that the egg from which you sprang was formed inside your maternal grandmother.) What’s more, pregnancy costs a woman nine months, while the initial male contribution to parenthood generally requires no more than a few minutes.

Read more at Time Magazine.