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Boiling Point

Heated dispatches from the parenting front lines

The puberty gene: Why some girls grow up fast

by Terri Mauro
March 28, 2001

Early puberty is in the news again, but this time the theories don't have anything to do with environmental pollutants or lack of exercise. This time, researchers are speculating it's all in the genes.

According to a report on InteliHealth, scientists first looked into the genes responsible for the production and utilization of estrogen, but found no connection. They hit the jackpot, though, with a gene whose responsibilities include producing a liver enzyme and breaking down testosterone. A particular variation on that gene seems linked to early puberty: almost all girls with two copies of the variation start developing breasts before age 10, while half of girls with one copy and 40 percent with none begin that early.

The researchers posit that by reducing testosterone, the gene triggers the rush of estrogen that gets puberty going. Since the gene is vital in other ways, there's no call to start tinkering with it. But the possibility does exist that scientists may be able to screen girls to find out early whether they're at risk for early puberty onset, so that special measures such as making sure they stay active and keep their weight down can be taken to stave off the inevitable.

Why worry about early puberty? For one thing, it can cut inches off a girl's final height, since vertical growth slows after that developmental landmark. (Of course, since I'm only 4'10", I can reassure parents that indeed, there is a full and productive life under 5 feet.) For another, longer exposure to estrogen means a greater potential for breast cancer later in life. And for another, some people are just distressed by the thought of second or third graders with breasts and periods. (Well, I have a third grader with breasts, and as she would say, it's not the end of the world. Of course, she is almost 11, and so entitled to them. But I can't say I'm too upset at the idea that some of her younger classmates may prematurely join her.)

Anything that increases our knowledge of what's going on with our kids is good. And anything that can prepare families to anticipate problems in a pro-active way is good, too. But when I hear about screening girls for the early-puberty gene, all I can think about is those overambitious adoptive parents who want assurances that they're not going to bring home anything the least bit out of the ordinary. I imagine them writing to international adoption forums and asking if their prospective adoptive daughter can't be screened for the gene, because goodness gracious, they wouldn't want to deal with early puberty.

Anything that increases our knowledge is good; anything that makes a child undesirable in return is bad.