A woman’s expectation of her life span can influence their babies’ gender

A study by biological anthropologists at University of Kent has revealed that contemporary, British women who believed they had a longer time to live, were more likely to give birth to a son than women who thought that they would die earlier.

According to Dr Sarah Johns, who led the research, this may be because it requires more effort to be pregnant with, give birth to, and raise a son to adulthood.

The study, which is published today in the journal Biology Letters, suggests that the sex ratio even in a relatively affluent, Western setting can be influenced by how a woman views her future health and environment. Earlier studies have shown that poorly nourished mothers were more likely to give birth to girls, but this was a link that has only been established in developing countries.

The findings are a result of a survey of British women who had recently become mothers. More 600 women in Gloucestershire were asked to what age they expected to live. The results indicate that people’s perception of their future wellbeing influences the proportion of sexes in the population.

The work was funded by the ORS Awards Scheme, the University of Bristol, and from a grant received by Gloucestershire's Teenage Pregnancy Strategy from the Department of Health's Teenage Pregnancy Implementation Fund.