title: Secondary sexual characteristics in boys: data from the Pediatric Research in Office Settings Network.
abstract: BACKGROUND
  Data from racially and ethnically diverse US boys are needed to determine ages of onset of secondary sexual characteristics and examine secular trends. Current international studies suggest earlier puberty in boys than previous studies, following recent trend in girls.
  
  
  METHODS
  Two hundred and twelve practitioners collected Tanner stage and testicular volume data on 4131 boys seen for well-child care in 144 pediatric offices across the United States. Data were analyzed for prevalence and mean ages of onset of sexual maturity markers.
  
  
  RESULTS
  Mean ages for onset of Tanner 2 genital development for non-Hispanic white, African American, and Hispanic boys were 10.14, 9.14, and 10.04 years and for stage 2 pubic hair, 11.47, 10.25, and 11.43 years respectively. Mean years for achieving testicular volumes of ≥ 3 mL were 9.95 for white, 9.71 for African American, and 9.63 for Hispanic boys; and for ≥ 4 mL were 11.46, 11.75, and 11.29 respectively. African American boys showed earlier (P < .0001) mean ages for stage 2 to 4 genital development and stage 2 to 4 pubic hair than white and Hispanic boys. No statistical differences were observed between white and Hispanic boys.
  
  
  CONCLUSIONS
  Observed mean ages of beginning genital and pubic hair growth and early testicular volumes were 6 months to 2 years earlier than in past studies, depending on the characteristic and race/ethnicity. The causes and public health implications of this apparent shift in US boys to a lower age of onset for the development of secondary sexual characteristics in US boys needs further exploration.
authors.affiliation: Department of Maternal and Child Health, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, 1450 Russell Chapel Road, Pittsboro, NC 27312, USA. mherman-giddens@unc.edu
authors.forename: Marcia E
authors.initials: ME
authors.lastname: Herman-Giddens
authors.forename: Jennifer
authors.initials: J
authors.lastname: Steffes
authors.forename: Donna
authors.initials: D
authors.lastname: Harris
authors.forename: Eric
authors.initials: E
authors.lastname: Slora
authors.forename: Michael
authors.initials: M
authors.lastname: Hussey
authors.forename: Steven A
authors.initials: SA
authors.lastname: Dowshen
authors.forename: Richard
authors.initials: R
authors.lastname: Wasserman
authors.forename: Janet R
authors.initials: JR
authors.lastname: Serwint
authors.forename: Lynn
authors.initials: L
authors.lastname: Smitherman
authors.forename: Edward O
authors.initials: EO
authors.lastname: Reiter
mesh_terms: D000293:Adolescent; D001741:Black or African American; D000367:Age Factors; D002648:Child; D006630:Hispanic or Latino; D006801:Humans; D008297:Male; D011627:Puberty; D012727:Sex Characteristics; D012741:Sexual Maturation; D014481:United States; D044465:White People