It’s never easy to be 13 — especially when you’re actually only eight. If there was one good thing about the unavoidable storms of puberty, it was that you could at least predict when they’d come. After 11 or 12 years of a relatively uncomplicated childhood, you would slowly begin the transition to your teen years and beyond. No more.
Increasingly, puberty in both the developed and developing world is beginning as young as age eight, seven or even earlier. In the U.S. two out of every 10 white girls, three out of every 10 Hispanic girls and four out of every 10 African American girls are showing breast development by age eight. Onset of puberty is falling for boys too — with doctors not even considering it a clinical problem unless the physical changes begin before age 9. It’s girls, however, who are being hit the hardest.
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The American obesity epidemic is surely to blame — at least in part — since fatty tissue can increase the body’s output of certain hormones. So too may the agricultural hormones found in meat and dairy products. And so too may industrial chemicals, especially phthalates and BPAs in plastics, which are known as endocrine disruptors for their tendence to mimic, block or otherwise interfere with the function of hormones.
Kids whose puberty begins too soon face not just psychological risks, but physical ones too, with an increased likelihood of cancer, as well as skeletal changes that could prevent them from attaining their full adult height.
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Drug therapies to shut off puberty are available, but is this really what we’ve come to — injecting preteens with hormone and growth regulators to control a process nature had already figured out perfectly well? TIME’s investigative story, “Little Women,” appearing in the current issue (and available to subscribers here), explores what’s behind the plummeting age of puberty, and what we can do — must do — to fix the problem.
Jeffrey Kluger is a senior writer at TIME. Find him on Twitter @jeffreykluger. You can also continue the discussion on TIME’s Facebook page and on Twitter at @TIME.