New studies are confirming that American girls are continuing to enter puberty at younger and younger ages, with obesity and chemical contaminants among the leading culprits.

FoxNews.com is reporting on data from a long-term study of more than 1,200 girls in several major U.S. cities which found that, on average, African American girls are showing signs of breast development at eight years and 10 months. Hispanic girls are showing development by nine years and four months, and white and Asian girls by nine years, eight months.

"For white girls, puberty hit about four months earlier than in a 1997 study that also measured breast development," Fox reports. "That study concluded girls were entering puberty earlier than in the past."

Writing in Pediatrics earlier this month, Dr. Frank Biro and his colleagues named rising obesity rates as one of the prime drivers behind the early puberty rates.

Other factors are the amount of exercise a girl gets and the many chemicals in the environment that mimic hormones.

"One of our challenges is going to be there are literally hundreds of chemicals that could be candidates," said Biro, who works in the adolescent medicine division at Cincinnati Children's Hospital Medical Center in Ohio.

The study did not look at when girls started menstruating, which usually happens within two to five years after breast development begins.

These findings are worrisome because maturing at a younger age could come with long-term risks for girls, such as placing them at a higher risk of breast and other cancers because of how much longer their bodies are exposed to estrogen.

Another problem is that girls who develop at younger ages also tend to become sexually active sooner. They are also known to use drugs and alcohol and to become depressed or develop low self-esteem, Fox reports.

"One of the things the parents of these early maturing kids need to do is they need to monitor them more closely," and to talk about sex earlier, Biro told Reuters Health.

Dr. Anders Juul, who heads the Department of Growth and Reproduction at Rigshospitalet in Copenhagen, Denmark and who wasn't involved in the new report, said he doesn't think parents should be overly worried.

"I think the scary part is not (for) the actual girl, because we don't know what it means for her," he told Reuters Health. "It is a warning that something is influencing our child population and it calls for concern and continued studies."

© All Rights Reserved, Living His Life Abundantly®/Women of Grace®  http://www.womenofgrace.com