Is there any truth to reports that girls are hitting puberty earlier these days?
The timing of puberty is influenced by many factors, most importantly genetics (ethnic group, timing of parents' puberty, etc.). Of the environmental factors that affect puberty, nutritional state is the most important. Other possible environmental factors include endocrine-disrupting chemicals (such as pesticides), stress, climate and light. It has long been known that heavier children tend to go into puberty at a younger age than do thinner ones. So, given the explosive rise in obesity among children in the U.S., obesity may well be contributing to an earlier onset of puberty.