Boys starting puberty up to two years earlier at the age of nine

Previous studies have shown that girls have begun starting puberty as early as the age of nine.

Journal Pediatrics – Secondary Sexual Characteristics in Boys: Data From the Pediatric Research in Office Settings Network

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. The earliest mean ages being 9.6 and 9.7 for Hispanic and African boys.

9-20 percent of boys could begin showing signs of puberty at the age of six

10 to 23 percent of girls show signs of puberty at the age of 7

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