According to a new study, American girls are hitting puberty earlier than ever before and experts agree obesity may be to blame. It’s thought that steadily increasing rates of childhood obesity may play a large role in some girls’ earlier development because body fat is linked to the production of sex hormones. When findings were compared to the 1997 figures, girls in the current study were found more developed at a younger age. About 10% of the 7-year-old white girls and 23% of 7-year-old black girls showed signs of breast development, a jump from the 5% of white 7-year-olds and 15% of black 7-year-olds in 1997. Among the 8-year-olds, some 18% of white girls and 43% of black girls already had started puberty, which was an increase of 11% for white girls from 1997 and the same increase for black girls. The pattern of reaching puberty early is cause for concern as early puberty may put girls at a higher risk for breast cancer, and girls who reach puberty early are more likely than their peers to take risks, according to the study’s authors. Also, developing faster than one’s peers can have adverse psychological effects.