Jonah Lehrer lobs grains of salt at a UCLA study finding that children don't increase happiness:
The fact of the matter is that it's much easier to quantify pleasure on a moment-by-moment basis, or document the swing of cortisol levels in saliva, 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 provide a profound source of meaning. (I like the amateur marathoner metaphor: survey a marathoner in the midst of the race and they'll complain about their legs and that nipple rash and how the endless route. 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.)
I am in awe of you.