Biology 103
2000 Third Web Report
On Serendip

"Marissa Carter, a Galveston, Texas, housewife, could not believe it when her daughter Sharon, at the tender age of 4, seemed to be developing breasts. The tiny buds that appeared on the little girl's chest were gone within a couple of weeks, but three years later, they reappeared, and this time they grew--along with pubic hair and hair in Sharon's armpits. "I felt this was too early for her to be developing," recalls Carter. ŒGosh, I was flat as a board at her age.'"(1).

This is one of many cases that have been reported in the past decade. Everyone can agree, it seems as through everywhere you turn, girls are looking more and more like they belong in high school. Dr. Micheal Freemark, Chief of Pediatric endocrinology at Duke University Medical Center, claims he encounters girls from ages five to ten with breast or pubic hairs everyday in his clinic. The question is; What is going on? Scientist believes it is a number of things ranging from chemicals to obesity. But the fact still remains, all anyone knows for certain is the signs of sexual development in girls are appearing at younger ages. (1).

Puberty is a process of biological maturation. It begins in late childhood or early adolescence and includes all the physical changes that young people undergo during the passage from childhood to adulthood. Both the onset and duration of puberty are characterized by tremendous variations such that some girls complete puberty before others begin. The age when puberty begins varies so much that it is somewhat misleading to discuss the "average" age of onset. In girls, puberty may begin as early as 7 or as late as 13. The puberty processes of biological change may take anywhere from 18 months to six years for girls to complete. The variation in the onset and duration of puberty can be a source of stress for young people, especially if they are early or late blooming.

A recent nationwide study published in Pediatrics raises concerns that incidences of early puberty and other forms of early sexual development may be increasing in the U.S. Nearly half of all black girls and 15 percent of white girls, the study says, are beginning to develop sexually at the age of eight. For some, the trend starts even earlier, and is known as precocious puberty: Three percent of black girls, and one percent of white girls, show signs of sexual development as early as the age of three. (2).

"When I was in clinical practice examining children, colleagues and I noticed that an unusually large number of girls already were developing sexual characteristics" says one of the authors of the early puberty study, Dr. Marcia E. Herman-Giddens of the University of North Carolina at Chapel Hill School of Public Health. The Pediatrics report contradicts standard pediatric textbooks and earlier U.S. studies about the average age that girls begin to mature. The study found that, on average, black girls begin the process between eight and nine years and white girls by age 10. Black girls are, the study says, entering puberty approximately one to one and a half years earlier than white girls and beginning menstruation approximately eight and a half months earlier.

Due to the uncertainties that exist around this new phenomenon of early puberty, it becomes more difficult for scientists to pinpoint the exact cause of early development. There has been much support among scientist around the idea that early puberty is some how connected to weight gain. In 1996 the Children's Nutrition Research Center in Houston conducted a study and found children are larger proportioned and taller than they were three decades ago, but much of that bulk is fat, not muscle. They center also concluded that American children of all races are getting fatter, which could be a factor in triggering early puberty. The Houston study found that twenty years ago, one in six girls had more than the thirty two percent body fat - the threshold for obesity in women. One in six boys were considered obese then. Today, one in three American girls and one in four boys have the body fat proportions that designate them as obese. (2).

Scientist has known for a very long time that very over weight girls mature earlier and very thin girls tend to mature later. Exactly why obesity and development should be linked is not well understood. Dr. Paul Kaplowitz, a pediatric endocrinologist with the Virginia Commonwealth University School of Medicine suspects that a protein may encourage early breast development called leptin. "We know that fat cells produce leptin and leptin is necessary for the progression of puberty". Also, overweight girls have more insulin circulating in their blood. Higher levels of insulin stimulate the production of sex hormones from the ovary and adrenal gland. (1).

Another explanation is chemical pollution in the food chain, specifically, DDE, a break down product of the pesticide DDT, and PCBs, both these chemical mimic hormones that play a very important role in the development of the reproductive system. There was a study based on this idea which is being conducted by Dr Walter Rogan, an epidemiologist at the National Institute of Environmental Heath Sciences. He chose six hundred pregnant women and measured the chemical in their bodies and then when their babies were born, the researchers measured the levels in the mothers breast milk, and finally, the children were monitored as they grew into puberty. What was found was that boys exposed to DDE and girls exposed to PCBs were heavier than their unexposed peers were. They study also found that girls with high prenatal PCB exposure tended to hit the first stages of puberty a bit earlier. (1).

There has also been several studies that found puberty might occur earlier among adolescents who have grown up in less cohesive, more conflict-ridden environments. One researcher found that girls who grow up in homes without biological fathers might mature earlier than girls whose fathers are involved in their lives. Some researchers also theorize that there might be a biological relationship between the absence of males in households and problems such as teen-age pregnancy and the apparent increase in behavior disorders in young boys. Another idea is stress is playing a role in early maturation. Sources of stress may include troubled family situations, the desperate conditions in many poor neighborhoods and schools, or the proliferation of media images of sexual stimulation on television. There are many scientists who agree with the idea of media images causing early puberty. The sexualized messages could be triggering changes in the brain that are jump-starting development. (2).

What ever the causes may end up being, it is clear that the effects on these girls are even greater. Puberty alone is a stressful point in the development of a young girl. The new Girl Scout Research Institute (GSRI); conducted a study called Girls Speak Out: Teens before Their Time. The researchers found that todayıs pre-teen girls are suffering greater stress as a result of this "developmental compression" and need trusted and reliable sources of information to address their many questions about body image, relationships, sexuality and the future. (4).

Raising a strong, self-confident daughter in today's complex world can seem like a monumental task for many parents. Physically, emotionally, and cognitively, girls are maturing at an earlier age than in generations past. Coupled with the pressures from mass media to grow up too fast, girls are facing issues of adolescence at a younger and younger age. It is important that parents keep communicating with their daughters. Having a continuous dialog going will help a lot. Having your daughter know that you are open to any all questions that they may have about their physical changes is critical. Also letting your daughter know that these changes are natural and happens to everyoneŠeven boys.

WWW Sources

2)Younger Children with Teenage Looks,

3)Puberty can begin at 8 in girls,

4)Girls Speak Out: Teens Before Their Time,

5)Early Puberty. (environmental causes of early puberty in girls) ,

6)Early puberty turns girls into women ,

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