Researchers looked at the diets of 244 pregnant American women via a food frequency questionnaire during the second trimester. They found that women expecting a boy had an eight percent higher intake of protein, a nine percent higher intake of carbohydrates, an 11 percent higher intake of animal fats, and a 15 percent higher intake of vegetable fats than women who were carrying a female embryo. The gender of the newborn had no effect on maternal weight gain, even though weight gain is linked to birth weight. These findings support the theory that women carrying male rather than female embryos may have higher energy requirements and that male embryos may be more susceptible to energy restriction, say the authors. The researchers hypothesize that the signal from the fetus responsible for the higher energy intake of women carrying a boy could be related to the strongly anabolic testosterone secreted by the fetal testicles; however, further research is needed. The research was supported in part by a grant from the National Institutes of Health.