Mothers outnumbered fathers throughout much of human history, a new DNA analysis of people around the world shows.
The genetic findings offer evidence for polygyny, when one man has many wives, and other reproductive customs, as people migrated out of Africa.
"[Historically] more of the women were reproducing than the men," study researcher Mark Stoneking, a professor of biological anthropology at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, told Live Science in an email. "This often happens in human societies, because not all men are able to afford wives, or sometimes a few men will have many wives."
These practices resulted in females making a larger genetic contribution to the global population than males did, the researchers found.
Stoneking and colleagues used a new method to scrutinize genetic variation within the male Y-chromosome. By looking at one part of the Y chromosome, they found all of the genetic variants, or slight differences in the order of DNA's "letters," within that region.
Previous studies had only looked at some of the variants, leading to unreliable data, because "you only find out about genetic variants that you already know about, and not about new genetic variants," Stoneking said.
Read the full, original story: Humanity has more mothers than fathers, DNA reveals