Even 60,000 years ago men had the wanderlust more than women.   Or they left families behind until they knew what they would find.

For one reason or another, the modern humans left Africa in a migration that many believe was responsible for nearly all of the human population that exist outside Africa today didn't have men and women as equal equal partners in that exodus. By tracing variations in the X chromosome and in the non-sex chromosomes, researchers from Harvard say they have found evidence that men outnumbered women in that migration.

The scientists expect that their method of comparing X chromosomes with the other non-gender specific chromosomes will be a powerful tool for future historical and anthropological studies, since it can illuminate differences in female and male populations that were inaccessible to previous methods. 

While the researchers cannot say for sure why more men than women participated in the dispersion from Africa—or how natural selection might also contribute to these genetic patterns—the study's lead author, Alon Keinan, notes that these findings are "in line with what anthropologists have taught us about hunter-gatherer populations, in which short distance migration is primarily by women and long distance migration primarily by men."