Testosterone has been getting teenage boys in trouble for centuries, but modern teens are in more danger than those in the past.
A new study has found that today's young men reach sexual maturity at 18 years old, four years earlier than males of 1800.
But while their bodies are all grown up, modern teens' brains are lagging behind, leading to reckless behaviour.
This combination of mature body and immature brain can be deadly, study leader Joshua Goldstein from the Max Planck Institute for Demographic Research said.
"Earlier risk-taking among males may be dangerous because it occurs at an age when young men are less mentally and socially mature," he said.
Goldstein studied death records from five European countries, paying particular attention to the 'accident hump' — a testosterone-fuelled surge in deaths that occurs when men reach physical maturity.
He found that the average age this surge happened fell steadily from 1750 to 1950 due to swelling testosterone levels.
The reduction happened at a rate of 2.5 months a decade, meaning that modern men reach their hormonal peak four years earlier than their 18th century counterparts.
Goldstein said improved standards of living, nutrition and medicine could all have contributed to the shift.
Several studies have shown girls are starting to menstruate earlier but it has been difficult to prove boys are similarly affected. Anecdotal evidence suggested they were, with the average age a choirboy's voice broke dropping from 18 in the 18th century, to just 13 in the 20th century.
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