While early puberty has long been documented in girls, a University of North Carolina researcher has found that American boys are also entering puberty earlier than ever, reports New Scientist (Sept. 22, 2001). Marcia Herman-Giddens surveyed more than 2,000 boys and found that they began puberty at an average age of 12, six months earlier than previous studies had found. 'I think a lot of it is environmental,' says Herman-Giddens, who is particularly concerned about the effects of endocrine disruptors, such as pesticide residues.