Want a boy? Have a high-calorie diet

According to the study led by Cheryl Rosenfeld of the University of Missouri, women who eat a full breakfast and a high fat diet at the time of conception are more likely to have a boy, while a low fat diet with periods of long fasts favours girls. “High calorie diets generally favour birth of males over females, whereas low calorie diets tend to favour females over males,” said Rosenfeld.

“In humans and mice, food restriction and a suboptimal diet during the period around conception and early pregnancy also lead to a surfeit of daughters, most probably due to selective loss of male foetuses, the most vulnerable sex in the womb,” he added. The researchers came to the conclusion after analysing the genes in placentas of pregnant mice fed diets high in fat or carbohydrates and low calorie diets.

They found that each one had a distinctive effect compared with a third group given normal soybean meal-based food, the “Telegraph” reported. After 12 days — just over half the animals’ pregnancy term — there were differences in almost 2,000 genes including those involved in kidney function and smell, according to the research published in Proceedings of the National Academy of Sciences.

They also found that female foetuses were more sensitive to their mother’s diet and there genes were more likely to be affected or altered. The team concluded that gene expression in the mouse placenta is “adaptive and shaped by maternal diet” with the biggest effect on the placentas of females.

“The reason why a maternal high fat, low carbohydrate diet favours survival of sons and a maternal low fat, high carbohydrate diet results in more daughters continues to elude us,” the researchers added.