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 to coincide with the AAP National Conference & Exhibition in New Orleans. 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.
This new research found that the observed mean ages of stage 2 genital and pubic hair growth, and early testicular enlargement - standard indications of pubertal onset - were six months to two years earlier than documented by data several decades earlier. Pediatricians recorded the earliest stage of puberty as occurring in non-Hispanic white boys at age 10.14 years; in non-Hispanic African-American boy at age 9.14 years, and in Hispanic boys at age 10.4.
Overall, African-American boys were more likely to start puberty earlier than white or Hispanic boys. Study authors say the causes and public health implications of an apparent shift toward a lower age of puberty onset for boys is unclear and warrants further research.