MORE US girls are starting puberty younger, with large percentages developing breasts and pubic hair as early as seven, according to a new study.
Nearly a quarter of black girls (23.4 per cent), 14.9 per cent of Hispanic girls and 10.4 per cent of white girls develop breasts by the age of seven, the study of 1239 girls in Harlem, Cincinnati and the San Francisco area found.
Twenty per cent of seven-year-old black girls had pubic hair, as did around 6.5 per cent of white and Hispanic girls, the study, published in the American journal Pediatrics, found.
The figures are a big jump compared with a similar study published in 1997. Back then, only five per cent of seven-year-old white girls and around 15 per cent of black girls of the same age were developing breasts.
Negative impacts associated with early puberty in girls include increased risk of breast or endometrial cancer later in life, and psychological troubles ranging from low self-esteem and eating problems to depression and suicide.
Scientists believe the phenomenon could be linked to obesity or exposure to chemicals in the food chain, and is putting girls at greater long-term risk of breast cancer. Several artificially produced chemicals have been blamed for interfering with sexual development, notably bisphenol A, a plastic found in the lining of tin cans and babies' feeding bottles. The constant exposure of girls to this chemical during their development stages in life is said to possibly contribute to the increased rate of girls reaching puberty at an earlier age than previous generations.
In the 19th century, girls faced the onset of puberty at around 15 years of age and for boys it was 17. Whereas today girls hit puberty at around 9 and boys at around 12 which reflects a steady decrease in the onset of puberty for girls and boys.
The study, led by Frank Biro of the Cincinnati Children's Hospital's adolescent medicine division, also said girls who hit puberty young are "more likely to be influenced by deviant peers" and become sexually active earlier.
The study found that at age eight, more than four in 10 black girls (42.9 per cent) were developing breasts and nearly a third had pubic hair.
Nearly 31 per cent of Hispanic girls and 18 per cent of white girls were developing breasts at the age of eight, and 19 and 10 per cent respectively had pubic hair.
Source: ‘The Australian’ and ‘Nine MSN’ 10/8/2010
