Being fat is 80% of it.
Genetics is 20%.
Blacks and Hispanics just mature earlier and die earlier.
(And, yes, I just made up the 80/20 ratio on a hunch.)
Precocious Puberty: eMedicine Pediatrics: General Medicine
by PB Kaplowitz - Cited by 2 - Related articles
29 Mar 2010 ... Body fat. An increased body mass index (BMI) has been associated with early puberty.14 In some studies the association is stronger in white ...
emedicine.medscape.com › ... › Endocrinology - Cached - Similar
Oh my gosh! Made it up?
You must be a scientist.