Why are girls starting puberty earlier, now?

Answer 1

I have been reading this book about how things are made now. In this book (listed below) it says that children are growing faster (hitting puberty sooner) because of the growth hormones that are given to the animals that we end up eating thus we consume these hormones too. I thought all the stuff I have been hearing is a bunch of mumbo jumbo, but as I read tis book it all made sense. These growth hormones are also making us FAT.
Check this book out!

Answer 2

Honestly, I don't know for sure. I think it might have something to do with eating a diet higher in fat and being less active less.