News Scan Briefs; July 2003; Scientific American Magazine; by Charles Choi, Philip Yam, Laura Wright, Steve Mirsky; 2 Page(s)

Sugar and Spice and Everything Nice:... Mother Goose may be right. Experiments in mice reveal that meals high in sweets and low in fats led female rodents to produce twice as many female pups than males. The reverse was true for mothers on low-sugar, lard-filled diets. The experiments, done by a group at the University of Missouri-Columbia, support decades of anecdotal evidence connecting diet to the sex of offspring in mammals. Meals could be hormonally swaying the female reproductive tract so that embryos of one sex have a survival advantage over the other. Diet could also affect how X or Y chromosome-bearing sperm fertilize eggs. Or, as team member Cheryl S. Rosenfeld notes, the energy content of the food could have skewed the sex ratios, because the fatty diet was higher in calories. The findings appear in the April 15 Proceedings of the National Academy of Sciences USA.-Charles Choi

Pass the Sushi: Mercury in fish eaten during pregnancy might not threaten children after all. University of Rochester researchers looked at the women of the Seychelles, who ate an average of 12 fish meals a week and had six times the mercury levels of a typical American, yet their children showed no meaningful cognitive problems. Past studies may have found a link because the women involved ate whale meat, which has five times the mercury concentrations of the more common ocean fish consumed in the Seychelles. The work appears in the May 16 Lancet-Philip Yam