Sleep around for healthier babies

It is the news Britain's Vicky Pollards might use to justify their behaviour.

Sleeping around can improve a female's chances of having healthier offspring, research shows.

Promiscuity in some mammals results in greater competition between sperm, with the winner having the best genes.

The discovery was first made in a study of a carnivorous mouse-like marsupial from Australia, Antechinus stuartii.

But the same evolutionary principle may also apply to other promiscuous mammals, such as chimpanzees. In controlled tests, each of 17 female marsupials mated with the same three males. In another group, 19 females were forced to be monogamous and take only one mate.