Very important. Any memeplex that has aims that happen to produce kids will have a edge. It just so happens few if any secular memplexes have made this possible.
But this is odd especially since values are arbitrary, is there really no value one can pursue that is best served (among other things) in having children (and perhaps attempt to imprint the same values on them)?
This, however, explains people who get incredibly upset at the notion of others not wanting children and brand them "selfish".
Its the same kind of upset a different kind of people have when they don't see someone ,who has already heard all the arguments for it, recycling.
Very important. Any memeplex that has aims that happen to produce kids will have a edge. It just so happens few if any secular memplexes have made this possible.
Another way a memeplex can succeed is by being very good at converting others. Note that such a memeplex if left unchecked could cause humans, or at least whatever culture it spreads in to evolve to extinction. As such leaders of other memeplexes may take extreme measures to suppress it.
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).