Congrats! That is awesome. In all seriousness, I think smart people are doing a favor for the world whenever they have another baby, because they contribute more than they "cost", in whatever metric you want - e.g. their average "carbon footprint" is negative because, on average, they solve problems like that.

I have seen so many brilliant colleagues focus on their career at the expense of having children ("I'll think about kids once I get tenure...at 38 yrs old"). I've found having a kid to be very fulfilling and fun, it's cool to see how the mind works by watching every little developmental step they take, and in some way you can take joy in things that have become mundane when you get to explain how they work to someone seeing them for the first time. Also, having someone who resembles you in certain ways takes some of that certain loneliness ("there's no one like me out there") out of life. Pinker and Harris have helped give me the right attitude about it: don't stress about how to parent, just enjoy it.