[Karsus]

http://www.mindfully.org/Health/Early-Onset-Puberty.htm#1
http://www.mugu.com/pipermail/upstream-list/2000-November/000851.html
http://www.gentlebirth.org/archives/puberty.html
http://www.ems.org/endocrine_disruptors/early_puberty.html

Some links may contain a few duplicate studies.

Looks to me like it is happening earlier and earlier.