Being either overnourished or undernourished before birth can alter gene activity, leading to obesity during adulthood, a study in mice suggests. The researchers predict that this finding could lead to more-tailored treatments for obesity in people.
Some scientists have proposed that obesity and a variety of diseases result from the conditions in which fetuses develop. To determine whether fetal changes in gene activity could initiate obesity, Frederick vom Saal of the University of Missouri–Columbia and his colleagues removed a single ovary from female mice. When these mice became pregnant, the eight or so fetuses that typically occupy both tubes of the mothers' uteruses crowded into a single tube.