British scientists said women on low-calorie diets or skipping breakfast at the conception time are more likely to have a girl than a boy, media reports Wednesday quoting Proceedings of the Royal Society of Biological Sciences as saying.
The new research by the universities of Exeter and Oxford provides the first evidence that a child's sex is associated with the mother's diet, and higher energy intake is linked to males. Women on low-calorie diets are likely to give birth to a female.
Skipping breakfast may be interpreted by the body as signaling low food availability, since it depresses levels of blood sugar.
Though sex is genetically determined by fathers, it is known that high levels of glucose encourage the growth and development of male embryos while inhibiting female ones, although the exact mechanism is unclear.
"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," said Fiona Mathews of the University of Exeter.
After studying 740 first-time pregnant mothers in Britain, Mathews and colleagues found 56 percent of those in the group with the highest energy intake at conception had sons, compared with 45 percent in the lowest group.