Here's a fun fact to throw out the next time you're dining with your aging parents: The risk of having a heart attack during sex is about the same as the risk you'll have one just from getting out of bed in the morning, meaning the risk is no more than usual [source: Block, Bakos]. In fact, Harvard researchers have found that sexual activity is a contributing factor in less than one percent of heart attacks [source: Hainer]. If you're worried that your dad might stray from mom in his older years, just remind him that most of those sex-related heart attacks occurred during cases of infidelity, when stress levels were likely higher [source: Block, Bakos].

Is your stomach churning at the mere idea of sharing such information with anyone over the age of 60, let alone your parents? You're not alone. Our society has a tendency to use sexually active seniors as comic relief -- in movies, for instance, the dirty old man or the randy grandma may serve as a foil for the real love story being told between young, beautiful, unwrinkled individuals.

While we may not like to think about it, sex isn't merely an activity for the young. In a study commissioned by the National Council on Aging, almost half of the seniors surveyed reported that they engaged in sexual activities at least once a month [source: Leary]. What's more, sex might get better with age -- the same survey found that 74 percent of sexually active men and 70 percent of sexually active women rated their satisfaction with their sex life as equal to or higher than their sex lives in their 40s [source: Leary].

However, comparing sex in your 70s to the sex you had in your 40s or your 20s isn't an apples-to-apples comparison. The process of aging does have an effect on some things that go on in the bedroom.