Why is puberty coming earlier for girls today?

Everyone who's been through puberty knows it can be tough. But what if the changes started early -- say at about age 6 or 7? Why are many girls starting puberty so young?

Early puberty & late puberty

How long does puberty last for girls? - Quora

How Not to Embarrass Your Tween

Girls are entering puberty a year earlier than their mothers' generation, Science

Puberty: Normal Growth and Development in Girls

Misconception: Drinking Milk Causes Early Puberty

How do faces change during puberty? - Quora

Like Girls, Boys Are Entering Puberty Earlier

Girls who do not live with both parents more likely to start puberty early - Kaiser Permanente Division of Research

Girls are entering puberty a year earlier than their mothers' generation, Science

Should we be worried about early puberty?, Health & wellbeing

Puberty In Girls: Causes, Signs, Stages And Duration