"A study conducted by the American Academy of Pediatrics (AAP) has documented that boys in the U.S. are experiencing the onset of puberty six months to two years earlier than reported in previous research. The study, Secondary Sexual Characteristics in Boys: Data from the Pediatric Research in Office Settings Network, will be published in the November 2012 Pediatrics and published online Oct. 20, 2012. The trend toward earlier onset of puberty in girls is now generally accepted and supported by extensive research. Until now, little research was available on the age of onset of puberty in boys in contemporary times. The study was designed and conducted through the AAP Pediatric Research in Office Settings (PROS) practice-based research network, a system of hundreds of pediatricians nationwide who contribute data to AAP-led scientific studies on children's health. A 1997 PROS study was the first large study to document earlier pubertal onset in US girls. For the study of pubertal characteristics in boys, 212 practitioners in 144 pediatric offices in 41 states recorded information on more than 4,100 boys."