Researchers want to do more studies to find out what might be causing this phenomenon. According to research first published in the medical journal Pediatrics in April of 1997, the age of the onset of puberty is getting earlier for girls, with the average age of either breasts or pubic hair showing up as 9.7 years for Caucasians and 8.1 years for African-Americans. Before this study of 17,000 girls evaluated by their pediatricians during routine examinations the norm for puberty onset was considered to be 11 years old, or one year later for white girls and two years later for African-Americans. In October 1999, a group of pediatricians redefined when puberty occurs in girls, so doctors could better identify when it was abnormal. Researchers have many theories, including an increase in obesity among children, low birth weight, absent fathers, unrelated males in the household, a sedentary lifestyle, chemicals that act as endocrine disrupters and the sexualization of children by the media.
Some research indicates that overweight girls have a tendency to reach puberty earlier.
Other work indicates girls may be exposed to pheromones, or sexual hormones, from unrelated men, such as stepfathers, prompting them to sexual development. Children who live in families without fathers may be experiencing stress, bringing about early puberty. Another theory is that the increase in images of sex on television fosters sexual maturity, in a way that food stimulates salivation. Myers spoke today at news conference on this issue in Washington. There are different factors playing a different role in different people.