Do you think all the hormones in our food these days contributes to girls starting their periods at an earlier age?

When I was a child, most girls were starting their periods at about 12–14. Many of my 10 year old daughter’s friends are starting their periods around 10 or 11. She’ll be leaving a “care package” in the nurses office this next school year just in case, as a couple of her friends were caught off guard this past year and had a horribly embarassing moment.

I was just thinking about how much our food has changed, and how many hormones are in our food these days. Do you think that has anything to do with periods starting earlier?