They're still learning how to read and write and add and subtract, but health professionals say girls as young as eight years old are starting to show signs of early puberty.

"I think body weight probably has a lot to do with why we're seeing girls have their periods earlier and really mature earlier," said Dr. Sujatha Reddy, and OB/GYN. 

Researchers report girls are now getting their periods around the age of 12, down from the average age of almost 15 in the late 1800s.  Doctors point to environmental toxins and weight gain.

"We know that the more fat cells a girl has, the more likely they are to have excess estrogen. That excess estrogen could raise concerns later on in a woman's life. The more estrogen you have exposed to your body, perhaps it increases the risk of breast cancer, possibly uterine cancer. and that's not the only worry. Their bodies may be maturing where their mind may not be and so that can, I think, cause some social pressures," said Dr. Reddy.

That could lead to social and psychological implications that a young girl may not be ready to deal with.