Clear link found between mother’s diet and child’s sex

Scientists say they have found a clear link between a mother’s diet and the sex of their child.

Researchers at the Universities of Exeter and Oxford claim their study shows that higher calorie intake around the time of conception is linked to the birth of sons.

They also found a strong correlation between women eating breakfast cereals and producing sons.

However they did not uncover a correlation between smoking, drinking and the body mass index (BMI) of a mother and the sex of her child.

The researchers also said that although this research provides the first link between a human mother’s diet and the sex of her offspring, there is still no evidence that diet during pregnancy, rather than around the time of conception, plays any role in the sex of a foetus.

They studied 740 first-time pregnant mothers in the UK who did not know the sex of their foetus.

The women were asked to provide records of their eating habits before and during the early stages of pregnancy and were then split into three groups according to the number of calories consumed per day around the time they conceived.

Over half (56 per cent) of the women in the group with the highest energy intake at conception had sons, compared with 45 per cent in the lowest group.

As well as consuming more calories, women who had sons were more likely to have eaten a higher quantity and wider range of nutrients, including potassium, calcium and vitamins C, E and B12.

Writing in the journal Proceedings of the Royal Society B: Biological Sciences, the researchers say the findings could shed light on the falling birth-rate of boys in industrialised countries, including the UK and US.

Lead author Dr Fiona Mathews of the University of Exeter said: “This research may help to explain why in developed countries, where many young women choose to have low calorie diets, the proportion of boys born is falling.

“Our findings are particularly interesting given the recent debates within the Human Fertilisation and Embryology Committee about whether to regulate ‘gender’ clinics that allow parents to select offspring sex, by manipulating sperm, for non-medical reasons.

“Here we have evidence of a ‘natural’ mechanism that means that women appear to be already controlling the sex of their offspring by their diet.”