Trend Of Earlier Puberty Continues Among US Girls

The age at which girls in the U.S.A. reach puberty is continuing to dip, with heavier weights and changing national demographics playing important roles, according to a new study. Research over the years has documented a gradual decline in the average age at which U.S. girls have their first menstrual period - from the age of 12.75 in the 1960s to about 12.5 in the early 1990s. The new findings, published in the Journal of Pediatrics, show that the trend has continued. National data for the years 1999 through 2002 put the average age at menarche - the first menstrual period - at just over 12.3 years, researchers at Tufts University in Boston found. For more information.