name webmdcom doheny k http wwwwebmdcom sex relationships features surprising health benefits sex surprising health benefits sex webmd reviewed chang l md ref increased immunity decreased risk prostate cancer sexual intimacy orgasms increase levels oxytocin helps people bond build trust long term study people ages clinical neuropsychologist david weeks md head old age psychology royal edinburgh hospital scotland said found sex helps look four seven years younger according impartial ratings subjects' photographs exclusive causation however unclear benefits may indirectly
Social science Sociology Sexology Human sexuality