Investigation into the sexual behaviour of young men.
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D003075:Coitus; D003267:Contraception; D006716:Homosexuality; D006801:Humans; D008297:Male; D008393:Marriage; D008418:Masturbation; D012537:Scandinavian and Nordic Countries; D012736:Sex Education; D011477:Sex Work; D012725:Sexual Behavior; D012749:Sexually Transmitted Diseases; D013223:Statistics as Topic