Danish girls are entering puberty a year earlier than they did just 15 years ago. US studies have found similar results, but were not as carefully controlled as this new study. Researchers studied 1,000 young Danish girls in 1991-1993 and another 1,000 young girls in 2006-2008. They used the same methods to find subjects and measure development. They found that girls today are beginning to develop breasts a full year earlier than they did in the 1991-1993 group.

In the earlier group, breast development began at an average of 10.9 years of age. The more recent group began developing breasts at an average of 9.9 years. While other markers of development such as onset of menses and pubic hair was also found to be earlier, the difference was less drastic with an average difference of 0.2-0.3 years earlier development. Researchers found that breast development was early even when they took looked at weight as a factor.

Early puberty can lead to more risk of breast cancer, ovarian cancer, polycystic ovarian syndrome and risky social behavior. PCOS is a leading cause of infertility. Girls who develop physically younger may not be ready to handle the increased social pressure to experiment sexually and therefore may engage in more risky behavior at a younger age. This is an example of one more reason we need to work to protect young girls from the social pressures of body image and too-early sexual pressure.

Environmental toxins from Bisphenol A (BPA) in baby bottles and other plastics to pesticides have all been tied to hormone disorders and early onset of puberty. Many different chemicals can act like hormones in the body or may disrupt normal hormone processes.

You can read more about this study here:

Puberty Study Article

An excellent book on helping young girls to help with the pressures our society puts on them is Reviving Ophelia. I highly recommend reading the book if you are a parent or loved one of a young girl.