Interesting. What would be the mechanism at work here?
Anecdotally, in my family, my mother was bf, menarche at 11; I
was bottlefed, menarche at 10; my daughter was bf (and grew up in
a much hotter climate than my mother and I), menarche at 13.....
I was under the impression that genes and climate were
important...Anybody? Judy Knopf in Beer Sheva, Israel