What a mother eats can influence baby's gender: study

Sharon Kirkey, The Ottawa Citizen

What a woman eats around the time she conceives may influence her baby's gender, a provocative new study has found.

British scientists who used data from 740 first-time mothers found those who consumed a few hundred calories more per day around the time they got pregnant were more likely to give birth to boys than women in the lowest calorie intake group.

Women also had a greater chance of bearing a boy if their diets were higher in potassium, calcium, and vitamins C, E and B12

What's more, "the consumption of breakfast cereals was also strongly associated with having a male infant," researchers from the universities of Exeter and Oxford report in a study published today in the journal Proceedings of the Royal Society B: Biological Sciences.

The study offers the first evidence yet of the link between maternal diets and gender and may provide insights into the falling proportion of male births in developed countries, where significant numbers of women of childbearing age are dieting, or skipping breakfast.

"There's so much excitement always in the birth of a baby, 'is it going to be a girl? is it going to be a boy?," says lead author Fiona Mathews, a lecturer in mammalian biology at the University of Exeter.

Ms. Mathews looked at newly pregnant first-time mothers with no medical problems (including obesity) recruited from a general hospital in the south of England. The women gave a detailed report of their usual diet in the year leading up to getting pregnant. They also kept detailed food diaries during pregnancy.

The women were split into three groups according to the number of calories consumed per day around the time they conceived. The team found that 56 per cent of women in the highest energy intake group had boys compared with 45 per cent in the lowest third.

When they went on to test whether any particular foods from a list of 133 were associated with infant gender, they found that 59 per cent of women who ate at least one bowl of cereal daily had a boy, versus 43 per cent of women who rarely or never had cereal. No other foods were significantly associated with infant sex.

Because cereal is the main food eaten for breakfast in Britain "it's a bit difficult to know whether it's just eating anything for breakfast, or cereal in particular," Ms. Mathews says.

Scientists have worried for years about the slight drop in the proportion of male babies born over the past 40 years -- and the study suggests changes in the diets of young women may explain why.

"Overall the energy intake of young women in western countries has fallen over 30 years," Ms. Mathews says. "So this might be one reason why we're then seeing this slightly falling proportion of male births."