hormones

Early Onset of Puberty in Girls Still a Mystery

A mystery to whom? Add estrogen-mimicking hormones to the environment (called xenoestrogens), give all sorts of growth-stimulating hormones to cows so they can mass produce milk, increasing rates of obesity (fat cells are a source of estrogen), destroy the GI’s normal flora (certain unfriendly flora unconjugate estrogen in the gut, essentially thumbing their bacterial noses at the liver’s attempt to get rid of the estrogen via the bile) and store everything possibly edible in plastic or vinyl (believed to act as a xenoestrogen) and the “mystery” is solved.

(article) Scientists have known for several years that girls and boys are reaching puberty earlier than in the past, but they still do not know why this is happening, or what the consequences might be, experts said at a forum here Monday sponsored by the Environmental Media Services. A study of 17,000 girls, reported in the journal Pediatrics in 1997, found that the average starting age of puberty among white girls had dipped a year from previous studies, to 9.7 years. African-American girls were found to reach puberty even earlier, at an average age of about 8, according to Dr. Marcia E. Herman-Giddens, the principal investigator and a professor at the University of North Carolina, Chapel Hill. Data on when puberty starts has been skimpy over the years — especially for African Americans. Still, Dr. Herman-Giddens said at the forum, “I am confident that this trend is a real trend,” adding that adolescence seems to be starting earlier and lasting longer in children worldwide. She is currently analyzing data on US boys. “What we’re seeing is a symptom of a very serious public health problem,” said Dr. Herman-Giddens, noting that the long-term physical and mental health effects of early puberty are not understood. Among the potential causes she mentioned are obesity or overweight, genetics, low birthweight, poor diet, lack of activity, and, surprisingly, an absentee father or a nonrelative male in the house. Scientists have also been exploring whether so-called endocrine disrupters — a group of chemicals thought to interfere with hormonal function — might be spurring or delaying puberty, Dr. Herman-Giddens noted. Dr. John Peterson Myers, director of the W. Alton Jones Foundation and author of a book on chemical contamination and fetal development, said that some of these chemicals have retarded sexual development in rat fetuses. Among the most controversial of these chemicals are phthalate esters, which are found in toys, vinyl flooring, detergents, and cosmetics and lotions. The science is not certain, but there is a plausible link, contends Dr. Myers. On Wednesday the Cosmetic, Toiletry and Fragrance Association released a statement noting that phthalates are widely used and have been favorably reviewed by the US Food and Drug Administration, the US Environmental Protection Agency, “and other scientific bodies in Europe, North America and Japan.” Dr. Diana Zuckerman, executive director of the National Center for Policy research for Women and Families, said that she worries about the psychological impact of early puberty on young girls. She explained that studies have shown that girls who develop at a young age begin dating earlier, have sex sooner, are subject to more psychological stress and behavior problems, and are more likely to drink and smoke. “No matter what they look like, they are still little girls,” she said. Dr. Zuckerman added that early puberty places stress on parents, who have to explain sexuality when their child is young.