As a parent of a child who was born with a near-fatal congenital disorder (malignant sacrococcygeal teratoma), I can attest that the decision to try for #2 is a

As a parent of a child who was born with a near-fatal congenital disorder (malignant sacrococcygeal teratoma), I can attest that the decision to try for #2 is a difficult one that we're still wrestling with. On the one hand ours was a one-off event and subsequent kids should be fine. We've always wanted two, and it's been such a wonderful experience that we want more of. So there's that. On the other hand, the months of treatment after diagnosis were the most emotionally draining experience we've ever gone through, and we don't know if we have it in us to go for number two. We're still in the early days (diagnosis + 9 months, all signs pointing to cured) so this may change, but active parenting causes healing and recovery to happen much slower. My wife (and her brother) are also both adopted, so we're well aware of the dynamics involved there. We've said since before we started trying for kids that we weren't going to beat ourselves up if we'd had problems conceiving (we gave ourselves nine months of trying before we'd look at adoption. As it turns out it only took us one). One could probably argue that the truly optimal thing to do would have been to forego trying biologically at all and to jump right into adoption, but that didn't feel right either. All of which is to say that I don't think it's egocentricity per se, but a natural desire to at least try and see your genes successfully expressed in the world. While that's not ideal from a rational perspective, I don't think you can go too far down that line of thinking without verging into eugenics.