After consultation with our medical team, they concurred that a de novo mutation for Bertrand was a strong possibility.

And, in truth, the conditional probability of de novo mutation for Bertrand was much higher than what actually happened--two independent mutations in the same gene colliding with one another.

If we had known the probability for Victoria was 1/4, we never would have gotten pregnant.

Ignorance was bliss.

Interestingly enough, adopted children tend to resemble their birth parents much more than adopted parents in the "Big Five" personality traits, and twins raised apart from each other resemble one another to a shocking degree. Bryan Caplan's book Selfish Reasons to Have More Kids discusses many of the studies that have examined these issues.

If you want a kid who is "like you," your optimal choice is probably to have biological children. The joys (and problems?) of being a parent, however, appear to be universal. Note that the first paragraph and Caplan's book are not an argument against adoption, but they are a reminder that genetics appear to have a much more powerful influence on people's personality than most Americans / Westerners wanted to believe for a very long time.

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.

There are perfectly good babies out there that need love and care, and by making your own you are basically saying "fuck them, the one that shares my DNA is better".

I don't think it's unreasonable to assume that my kids will turn out to have traits that I liked in me and my parents. Just because of that, I would rather conceive.

Or to phrase it another way, they're behaving the way animal species have for millions of years.

If it's not, I'd love to know what it is. Aww, downvotes from selfish people. Love doesn't require blood.