There are perfectly good multivariate regressions on happiness and kids and even good longitudinal studies. There is no excuse for looking at your own "simple estimate."
Will, that number actually is from a multivariate regression I did using the GSS. I thought it would be more engaging to report my own result than repeat someone else's. In any case, though, I could have made the same basic point using the Brooks regressions that you've blogged before: The negative effect of kids on happiness is small compared to e.g. the positive effect of being married. Brooks says the same thing; contrary to the title of your earlier post, he never said (and the data do not show) that children make us "miserable."
Given the size of the negative happiness effect of kids, there is nothing amazing about my claim that kids could easily have a positive effect on parental happiness if parents switched to a lower-effort parenting style. (Indeed, you've longed for a change in this direction yourself, at least for moms).
Furthermore, you don't seem to deny my point that, as behavioral geneticists teach us, lower-effort parenting would have little negative effect on children's futures.
So why is my argument so hard to "take seriously"?
Also, I have seen NO EVIDENCE that kids help make people happy when old, and mention none. But you keep asserting it anyway.
Actually, I have deliberately avoided saying that kids and grandkids make the elderly happier, precisely because I'm not convinced that the data bear this out. (Though I am confident that beeper studies would show that grandparents are really happy when they spent time with their grandkids). My claim, rather, is the more economistic one that when you are older you will, for whatever reason, prefer more children. Again, it's hard to argue with this. 60-year-olds with 4 kids may be no happier than 60-year-olds with 2 kids (and possibly 60-year-olds with no kids). But who wouldn't prefer to be the 60-year-old with 4 kids rather than a 60-year-old with 2 kids - or no kids?
And, again, you ignore the VERY high average costs of motherhood on women in terms of lifetime earnings, the realization of potential, social status, etc. You can argue that these costs can be mitigated, but it's shoddy and really does seem blithely misogynistic to ignore them.
I continue to ignore them for two reasons:
1. These costs are already well-known. People have already factored them into their decisions. I'm pointing out things that most people don't already know. The title was Selfish Reasons to Have More Kids, not Selfish Reasons to Have Kids.
2. If you look at the data - the same GSS data you favorably cite - you'll see that kids usually have a smaller negative effect on the happiness of moms than the happiness of dads. The natural inference is that you're missing half the story. Yes, women bear more of the costs of kids, but apparently they also get more of the benefits.
Incidentally, it's poor manners to suggest that I'm "blithely misogynistic." If I'm right, I'm helping women and men alike. If I'm wrong, there are plenty of simpler explanations than misogyny.
By the way, my desired family size is now -10.
That's unfortunate for the world, because you're an exceptional human being. But as I said before, I have no intention of nagging you to do what's best for the world. :-)