Why puberty starts earlier nowadays?

Question

I’ve seen a study which found that the age of puberty (especially female puberty) is dropping rapidly. In 1860 it started around 16.8 and in 2010 it was 10.8. Why is that? Is there any explanation?

In: Biology

Answer 1

The research suggests that menarche (first period) is tied to body fat percentage. As Americans have been getting fatter, puberty comes earlier. The effect is less pronounced in other countries that are less fat, like Japan.