when girls start getting breast development, and what they found is when you look at white girls in the mid early 1990s, 5% of 7-year-old girls starting puberty at age 7, being early. by the mid-2000s, it was 10%. when we look at african-american girls hitting puberty at age 7, about 23% of african-american girls have started puberty by age 7, and when you look at hispanic girls, 15% have started puberty at age 7. when we were growing up, that was unheard of to start puberty at age 7, more like 9, 10, 11. how old are you in the seventh grades? 11, 12. i think i was about 12. huge difference.