Women with feminine-looking faces are more likely to want lots of children, according to a new study.
Researchers found that women with facial features such as a smaller jaw and nose as well as larger eyes and lips were likely to want more children than those with masculine facial traits.
A separate study by the same group of psychologists at the University of St Andrews said high levels of the female sex hormone oestrogen are linked to how many children a woman wants.
The findings also suggest men may find certain women’s faces more attractive because they are more likely to bear children.
In one study, researchers at the university’s perception lab questioned 84 women about how many children they wanted, then created composite faces from the 18 women who wanted the most and the 18 who wanted the least.
When they showed the pictures to a group of men and women, they rated the women who wanted more children as most feminine-looking.
Previous studies have shown that oestrogen has an impact on facial appearance as it inhibits bone growth, leading to features such as a small jaw. Psychologist Miriam Law Smith, who led the study, said: “In terms of evolution, if a woman’s facial appearance signals aspects of maternal personality, as well as underlying fertility as we have previously shown, then what men find attractive could ultimately influence the size of the resulting family”.
In the other study, the team analysed the oestrogen levels of 26 women aged between 18 and 21 who had not had children.
The 26 also answered questions relating to their maternal desires.
Researchers found that women who said they wanted to have more children had higher oestrogen levels than those wanting fewer children.
Dr Law Smith said: “Women differ in what they see as an ideal family size; some may want a large family, for example four children, while others prefer only one child.
“We were surprised by the strength of the result between this maternal tendency and hormone levels, as so many social and cultural variables impact on how many children women will have, or will want to have.
“We know that oestrogen is strongly related to maternal behaviour in many other animal species but to see such a large correlation in humans is astonishing.
“Of course, we’re not saying that all maternal tendencies are related to oestrogen levels, because maternal tendencies are also shaped by our experiences, our background, our upbringing and a whole host of social and cultural factors.”