Onset of puberty in girls has fallen by five years since 1920, Children

No one is sure what is causing the change

TMHS 638: Early Onset Puberty Is Surging In Children - The Model

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Forty Years Trends in Timing of Pubertal Growth Spurt in 157,000 Danish School Children

What's the youngest age that a person can get pregnant and give

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Signs of Early Puberty and How It Affects Children

Childhood obesity 'to blame for early puberty

Physical Development in Girls: What to Expect During Puberty

1: Mean number of children by women's year of birth, 1920-1980 (in %)

Searching for Answers: Earlier Puberty Over the Last 200 Years

Children aren't starting puberty younger, medieval skeletons reveal

Child development - Wikipedia

Physical Development in Girls: What to Expect During Puberty

Puberty (Chapter Two) - The Neuroscience of Adolescence