Jonah Lehrer discusses a new study that shows children don't cause "happiness":
The fact of the matter is that it's much easier to quantify pleasure on a moment-by-moment basis that it is to quantify something as intangible as "unconditional love". Changing a diaper isn't enjoyable, and teenagers can be such a pain in the ass, but having kids can also be a profound source of meaning for people. (I like the amateur marathoner metaphor: survey a marathoner in the midst of the race and they'll complain about their legs and that rash and how the race seems like it's taking forever. But when the running is over they are always incredibly proud of their accomplishment. Having kids, then, is like a marathon that lasts 18 years.) The larger point, though, is that just because we can't measure something doesn't mean it isn't important, or that we should always privilege the quantifiable (pleasure) over the intangible (meaning). Real life is complex stuff.
The older I get the more it seems to me that the biggest difference is not between gay and straight, or even so much male and female, but between those who have children and those who do not.