Female populations have been larger than male populations throughout human history, according to research published today in the open access journal Investigative Genetics. The research used a new technique to obtain higher quality paternal genetic information to analyze the demographic history of males and females in worldwide populations.
The study compared the paternally-inherited Y chromosome (NRY) with maternally inherited mitochondrial DNA (mtDNA) of 623 males from 51 populations. The analysis showed that female populations were larger before the out-of-Africa migration and remained so throughout almost all subsequent migrations. The main drivers of this trend are likely to be processes such as polygyny, where one male mates with many females, and the fact that in most societies, women tend to move to live with their husbands. This has resulted in females making a greater genetic contribution to the global population than males.