By Grace Chua
WOMEN with high levels of a key sex hormone look and feel prettier, and could be more prone to cheating on their partners, says a study done by a researcher currently teaching at Singapore Management University (SMU).
The sex hormone in the study, oestradiol, is a form of oestrogen which has been linked to greater fertility. For instance, women dress more provocatively when oestrogen levels are highest, near ovulation when they are most fertile, said Dr Norman Li, a co-author of the study.
High levels of oestrogen are also linked to outward signs like larger breasts, attractive faces and curvier figures.
Social psychologists Dr Li of SMU and Ms Kristina Durante of the University of Texas, Austin (UT Austin) studied 52 female UT Austin undergraduates aged between 17 and 30 who were not taking hormonal contraceptives which would have interfered with natural oestrogen levels. Most of the women were Caucasians.
They tested each woman's saliva for oestradiol levels twice, as hormone levels fluctuate each month. The women were asked to rate their own attractiveness, and their photos were rated by others.
They were asked how many long-term and short-term relationships they had had, and about their sexual behaviour.
Dr Li and Ms Durante found that women with higher levels of oestradiol were rated as more attractive by themselves and others, and were more willing to cheat in a relationship - but not more likely to have a one-night stand.
Their study was published online this week in the journal Biology Letters. They concluded that such highly fertile women 'are especially motivated to be acquainted with other, presumably more desirable, men', in a strategy of 'trading-up'.
But Dr Li warned that the research showed only a correlation between oestradiol and infidelity. 'People shouldn't take it as deterministic. It doesn't mean that if you have higher oestradiol, you're going to cheat, and vice versa,' he said.
Future research might include a cross-cultural study of oestradiol, attractiveness and mating behaviour, or a study in which subjects' actions were tracked rather than self-reported, Dr Li added.
[The song says, "If you wanna be happy for the rest of your life, never make a pretty woman your wife. From my personal point of view, get an ugly girl to marry you. Anyway, it's correlational. Maybe people who are more likely to cheat produces more oestradiol. Or there is something else at work.]