Women with high levels of the sex hormone oestradiol may engage in opportunistic mating, according to a new study by psychology researchers at The University of Texas at Austin.
Doctoral candidate Kristina Durante and Assistant Professor of Psychology Norm Li published their findings in the Proceedings of the Royal Society of London: Biology Letters.
"The study offers further evidence that physiological mechanisms continue to play a major role in guiding women's sexual motivations and behavior," Durante said.
Durante and Li investigated the relationship between oestradiol, an ovarian hormone linked to fertility, and sexual motivation in a study of 52 female undergraduates not using contraception. Participants' ages ranged from 17 to 30 years old.
The researchers measured the participants' hormone levels at two points during each woman's ovulatory cycle and then asked them to rate their own physical attractiveness. Independent observers also rated the participants' physical attractiveness.
Participants also answered survey questions that measured their propensity to cheat on a partner.
The researchers found that a woman's oestradiol level was positively associated with self-perceived physical attractiveness. Women with a higher oestradiol level also reported a greater likelihood of flirting, kissing and having a serious affair (but not a one-night stand) with a new partner.
Oestradiol levels were negatively associated with a woman's satisfaction with her primary partner.
"Our findings show that highly fertile women are not easily satisfied by their long-term partners and are motivated to seek out more desirable partners," Durante explained. "However, that doesn't mean they're more likely to engage in casual sex. Instead, they adopt a strategy of serial monogamy."