A new study has concluded that women who sleep around could stop humans from becoming extinct.

Despite this being more risky for the individual, the study could solve the mystery of why females of most species have multiple mates.

The phenomenon of females having multiple mates is known as ''polyandry'' among scientists and is shared across most animal species, from insects to mammals. This study suggests that polyandry reduces the risk of populations becoming extinct because of all-female broods being born.

This can sometimes occur as a result of a sex-ratio distortion (SR) chromosome, which results in all of the Y chromosome ''male'' sperm being killed before fertilisation. The all-female offspring will carry the SR chromosome, which will be passed on to their sons in turn resulting in more all-female broods. Eventually there will be no males and the population will die out.

"We were surprised by how quickly - within nine generations - a population could die out as a result of females only mating with one partner. Polyandry is such a widespread phenomenon in nature but it remains something of an enigma for scientists. This study is the first to suggest that it could actually save a population from extinction," said Nina Wedell, lead author and a Professor of the University of Exeter. (With Input from Agencies)