Couples who have energetic, passionate sex are more likely to have a baby - that is, according to the Observer, who ran a full two-page article about it today and puported the virtues of sex which focuses on pleasure for both parties involved (versus routine, daily sex for the making of children only), because a boy will ejaculate more sperm when actually pleased, or something.
What the paper failed to mention is that energetic, passionate sex also helps with other things, like sleeping - as evidenced by myself about a week ago, when after birthday sex we managed to fall asleep with her wrapped in my arms, and woke up the next morning with the light still on - or today, when we had sex after a day or two of not having done so and ended up both drifting off (except I ended up dreaming about Voldemort in a library, and that was very disturbing).
I'm waiting for the article about the non-scientific, spiritual benefits of passionate, meaningful sex. Perhaps I'll write it some day, and upon opening the Observer at a table in a café bar with a tall cup of Joe I'll turn to one of the famous literacists I'm discussing the finer points with, and sneer, "Would you look at this headline? Good sex equals good sleep? I wonder who wrote this? Hope it's not that Innocent Loverboy bloke."