A Mother's Diet Influences the Gender of Her Future Child

There are couples give birth to so many babies they could literally form a football team, and all because of their desire of having a daughter. Others end up with a group of cheerleaders but a boy fails to make himself present. The answer is simpler than thought: a new study carried out at the Universities of Exeter and Oxford shows for the first time the connection between a child's gender and the mother's energy intake around the time of conception.

The 740 subjects were first-time pregnant British mothers in the UK, unaware of the sex of their fetuses. All subjects were of average weight, health and lifestyle. They completed a questionnaire tracking down their dietary habits before and during the early period of pregnancy. The subjects were assigned into 3 groups, depending on the quantity of daily calories intake around the time when they got pregnant.

56% of the women in the high calories intake group delivered sons, compared to 45% in the lowest calories intake group. Mothers of sons also were more likely to have had a more varied diet, richer in nutrients, like potassium, calcium and vitamins C, E and B12. Women consuming breakfast cereals were also more likely to have sons.

The research comes at a time when industrialized countries have been experiencing a slight but steady decrease, of one per 1000 births annually, in the ratio of newborn boys for the past 40 years. Other studies had shown a decline in the average calories intake in developed countries. The 'obesity epidemic' too is connected to decreased physical activity and junk food consumption. Skipping breakfast, a very negative habit for one's health (proven, oppositely to what many think, to increase bodyweight) is widespread now in developed countries: in the USA, it has boomed from 14% of the adults to 25% in the period between 1965 to 1991.

"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. 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," said lead author Dr Fiona Mathews of the University of Exeter.

In many animal species, plenty of food or high status makes females deliver more sons. This fact has been observed in many invertebrates, horses, cows and some deer species. It is an evolutionary trick used by females in order to further spread their genes.

"Potentially, males of most species can father more offspring than females, but this can be strongly influenced by the size or social status of the male, with poor quality males (delivered by starving mothers) failing to breed at all. Females, on the other hand, reproduce more consistently. If a mother has plentiful resources then it can make sense to invest in producing a son because he is likely to produce more grandchildren than would a daughter. However, in leaner times having a daughter is a safer bet," explained Mathews.

The gender is determined by the sex chromosomes of the father, but mothers could favor the development of male or female fetuses. IVF studies have already showed that high glucose levels boost the growth and development of male embryos while inhibiting female ones. Skipping breakfast just drops glucose levels, a fact read by the body as food shortage.

The research found no connection between a woman's smoking and caffeine intake during conception period and the gender of her future child. Also, the body mass index (BMI) of a mother did not bias the gender of the embryo.

MORE RELATED ARTICLES: The Unisex Brain Sexual Excitation and Inhibition in Men: Debunked Myths Sexual Inhibition: the No. One Factor Involved in Female Sexual Issues Your Level of Promiscuity Is Easily Read on Your Face The Secret for Big Muscles: Ibuprofen and Acetaminophen (Paracetamol) Grief Can Kill You This is How the Placenta Developed Top 10 Viral Infections Marijuana Alcoohol = Massive Brain Cell Death Fat-Rich Diet of Pregnant Women Translates into Future Obese Adult Progeny