So I found this post quite interesting:
http://www.gnxp.com/blog/2009/03/gnxp-readers-do-not-breed.php
(I'm quite sure that the demographics of this site closely parallel the demographics on Gene Expression).
Research seems to indicate that people are happiest when they're married, but that each child imposes a net decrease in happiness (parents in fact, enjoy a boost in happiness once their children leave the house). It's possible, of course, that adult children may be pleasurable to interact with, but it seems that in many cases, the parents want to interact with the children more than the children want to interact with the parent (although daughters generally seem more interactive with their parents).
So how do you think being child-free relates to rationality/happiness? Of course, Bryan Caplan (who is pro-natalist) cites research (from Judith Rich Harris) saying that parents really have less influence over their children than they think they have (so it's a good idea for parents to spend less effort in trying to "mold" their children, since their efforts will inevitably result in much frustration). And in fact, if parents did this, it's possible that they may beat the average.
(This doesn't convince me in my specific case, however, and I'm still committed to not having children).
I've wondered in the past if perhaps the best thing LW members could do if the singularity is more than 80 (4 generations) years away was simply to breed like Amish and adopt values of having many kids in the very late teens and early twenties early, focusing on higher education in the middling twenties and then after fifty spending most time on grandchildren whose parents followed the same patter and focus their late 20s and 30s on other goals.
Historical (Amish) population:
People underestimate just how much "dumb" replication can do to carry memes forward.
Edit: LW's help for a list of items is a bit confusing. If I remove item * in front of "historical Amish populations" from the above, the readable list of dates and population numbers collapses into a single poorly readable line. Can anyone explain this a bit further for me?
I would guess focusing on other goals while raising multiple pre-teen/early-teen kids wouldn't be that easy.