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Context: Since the 1980s, the age at which U.S. teenagers, especially minority youth, begin having sex has decreased. There is limited information on the relationship between early sexual initiation a...
Context: Past research has revealed that having a sister who gave birth as a teenager is associated with increases in young people's likelihood of engaging in risky sexual behavior. To date, however, ...
The powerful demographic trend toward aging of populations in most countries has appropriately focused attention on the health problems of older men. Although there is agreement that serum total, bi...

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