Ladies who have extra-marital affairs can blame it on their hormones, claims a new study, which found that women with high levels of estrogen not only look and feel pretty - but are also more prone to hop from man to man.
Estrogen, the so-called female hormone, affects fertility and makes women dress more provocatively.
Dr. Kristina Durante of The University of Texas at Austin and colleagues found that young women felt more attractive when they had high levels of an estrogen known as estradiol, and they acted on those feelings, reports New Scientist.
"These women are willing to trade up when the opportunity arises and continue to extract these lucrative resources from men when they can," says Kristina Durante, an evolutionary psychologist at the University of Texas in Austin, who led the study.
She thinks the behaviour could be an adaptation to the high costs of giving birth.
"For women it's all about the resources that we need. If you're going to be getting knocked up there's a significant cost," she says.
To reach the conclusion, Durante's team tested 52 female undergraduates aged 17 to 30 who were not taking hormone contraceptives. They took two estradiol samples from each, as hormone levels fluctuate from week to week.
They had the women rate their own attractiveness and showed their photographs to others to rate, as well.
As independent confirmation, a panel of two men and seven women also judged them the prettiest.
High oestradiol women reported that they had dated more men and were more willing to cheat, from innocent flirts to serious affairs. These women, however, proved no more interested in one-night stands than women with lower levels of estradiol.
The study has been published in the journal Biology Letters.