Scientists are speculating that two causes may be at play. The first: children are more obese than they used to be causing their bodies to make more estrogen. This could result in earlier menses. The second factor: chemicals in our environment called estrogen disruptors may also play a part in this shocking development. These chemicals are found in our food supply, our water and even in the tools with which we eat and drink.
Ten years ago there was debate whether some of the health changes that are rapidly appearing, such as autism, obesity, MS and premature menarche, were due to better collection of data. The data we are receiving now is collected in a modern time. These are real changes and real numbers.