More Research Needed on Early Puberty

N E W   Y O R K, Feb. 7, 2001 -- One day a few years ago, Marilyn Saunders noticed that her 8 ½-year-old daughter Susan was starting to develop small breasts and pubic hair.

It seemed odd to Saunders (not her real name), a 43-year-old mother from New York's Long Island, since she herself didn’t mature until she was older.

Her doctor told her not to worry: Early onset of puberty is now considered the norm by most pediatricians.

Early Puberty in Girls Is Norm

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.

What can be causing this premature pubescence? 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.

Causes May Include Obesity, Chemicals and Sex on TV

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.

“The picture is more complicated than a single cause or a single effect,” says Jeffrey Peterson Myers, director of the W. Alton Jones Foundation and co-author of Our Stolen Future, a book on endocrine-disrupting chemicals. Myers spoke today at news conference on this issue in Washington. “There are different factors playing a different role in different people.”

Researchers convened the news conference to bring attention to parents, educators, pediatricians and others, about this issue. They also called for more studies to understand how these different factors might be contributing to this problem.

“No one can really think that little girls in second or third or fourth grade should be developing breasts,” says Diana Zuckerman, a psychologist and executive director of the National Center for Policy Research for Women and Families.

This is the age, she says, when youngsters are being taught how many quarters are in a dollar. “These are young kids,” she says.

“How can you begin to explain to them why they might become moody or look different compared to other girls their age?” says Zuckerman. “Or why older boys might be interested in them? Are the teenage boys being nice, or flirting, or coming on to them? Even adult women sometimes have problems with these issues.”

If these children do not become aware of their blossoming sexuality, then they might become victims of sexual predators who see them as vulnerable, Zuckerman says.

Saunders says she still has difficulties talking to her daughter about sex. Her daughter is still so sheltered or emotionally immature that she cannot understand how someone could have a baby outside of marriage.

More Research Needs to Be Done

Marcia E. Herman-Giddens, an adjunct professor in public health at the University of North Carolina School of Public Health who authored the landmark study, says the psychological effects of early onset puberty need to be studied and data should be collected every 10 years to understand if the age is stabilizing or dropping.

“This is a serious public health issue,” Herman-Giddens says. “We don’t know about the sexual urges of 7- and 8-year-old girls and how they might affect their mental health.”

Zuckerman highlighted studies indicating psychological problems in girls who experienced early menstruation as a way to get a handle on what might be happening. Herman-Giddens did not find that menstruation started earlier in her population of girls, except among the African-American population. The age of the first periods for Caucasian girls was 12.8 years; for African- Americans, it was about six months earlier.

In a study of 6- to 11-year-old girls, those who matured earlier were more depressed, aggressive, socially withdrawn and had more sleep problems than those who hadn’t. Another study of 1,700 high school girls revealed that earlier menstruation was linked to drinking smoking, substance abuse, lower self-esteem and suicide attempts.

Whether boys are experiencing this early puberty is unknown. Research is ongoing about this question.

Myers says if research finds that some chemicals are contributing to early puberty, manufacturers might be apt to change the products they offer to consumers. Some studies in animals, he says, reveal that exposure to certain chemicals in the womb can lead to early sexual maturity later on. Other studies have indicated an association between exposure to certain chemicals called phthalates, found in plastics and cosmetics, and early breast development.

The cosmetics and plastics industries call their products safe.

Some Question if Early Puberty Is Real

But some pediatricians question the new puberty norm. Dr. Robert Rosenfield, professor of medicine and pediatrics at the University of Chicago Pritzker School of Medicine, challenges the methodology of the 1997 study, calling it biased in having too many girls with early puberty problems.

“The study was not done in a random fashion,” Rosenfield says. “The children were kids brought into a pediatrician’s office. … Early cases of puberty might be over-represented in the sample. Parents might have brought children in with a cold or a rash, but might have really been more concerned about early development of breasts or pubic hair.” A better study would have selected participants from the general population, he says.

Rosenfield says while most of these children may be all right by developing early, others may have some other medical condition that needs further study. Tumors and over-secretion of hormones by the adrenal gland can also lead to early development.

He agrees more research should be done to see if what Herman-Giddens found is real, but adds increasing childhood obesity may be a significant factor contributing to this issue.

While Saunders’ daughter is coping well with her early sexuality, her mother says she fears other parents promote teenage behavior in younger girls by allowing them to date and wear skimpy outfits.

“I think kids should be kids,” Saunders says. “They should be riding their bikes, playing, enjoying school and sports. They are innocent and should not being subject to the pressures of a teenager.”

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