Can Your Eating Habits Affect the Sex of Your Baby?

Studies show that a mother's diet at the time of conception influences whether she conceives a boy or a girl. Although sex is genetically determined by whether sperm from the father supplies an X or Y chromosome, it appears that a mother's body can favor the successful conception and development of a male or female embryo.

The first of these studies was conducted by researchers from Oxford University and the University of Exeter in England. This study established the initial evidence that a child's sex is related to a mother's diet. The study was published in the journal Proceedings of the Royal Society B: Biological Sciences and showed a link between higher energy intake around the time of conception and the birth of boys. This helps explain the reduction in the birthrate of boys in industrialized countries (a falling conceive baby boy rate), including the United States and Britain.

The findings of this study were based on an analysis of 740 first-time pregnant mothers in Great Britain who didn't know the sex of their fetus. These women provided records of their eating habits before and during the early stages of their pregnancy, and researchers analyzed the data based on estimated calorie intake at the time of conception. According to the study, among women who ate the most, 56% of them had sons, while among women who ate the least, 45% of them had sons. As well as consuming more calories, women who had sons were more likely to have eaten a higher amount and larger variety of nutrients. There was also a strong correlation between women eating breakfast cereals and producing sons. Other studies show that high levels of glucose enhance the growth of male embryos while inhibiting the growth of female embryos. Male embryos appear to be less viable in women who regularly limit food intake, such as skipping breakfast, which results in depressed glucose levels. A low glucose level may be interpreted by the body as indicating poor environmental conditions and low food availability.

The consistency of the trend offers an explanation for the consistent decline in the proportion of boys born to girls born in industrialized countries over the last 40 years, where even though women in general appear to be consuming more, eating habits have changed. In the United States, for instance, the proportion of adults eating breakfast fell from 86% to 75% between 1965 and 1991. And although women may be eating more overall, a nutrient-poor diet could be less favorable to a male embryo (resulting in a falling conceive baby boy rate). Glucose levels also may fluctuate in women who are dieting and trying to lose weight prior to pregnancy. Similarly, as with animals, more males are produced when a mother ranks high in the group or has plentiful food resources.