Art Carden, who is also expecting another child, is inviting economists to join his new Julian Simon Club:

Simon’s research shows that fears and worries about “overpopulation”
are senseless. Further, expressions of those fears and worries in
comments like “it is irresponsible to have more than two children” have
gained a wholly undeserved degree of social respectability. As an
aside, I think these are expressions of the kinds of non-material
status-seeking I discussed in this post. I discussed overpopulation in my 2009 Mises University lecture on “Environmental and Resource Economics,” and I provide some useful (?) links in an accompanying post.

I propose, therefore, that we create the Julian Simon Club. Just as Gregory Mankiw has created the Pigou Club
to recognize “an elite group of economists and pundits with the good
sense to have publicly advocated higher Pigovian taxes,” I propose that
we create the Julian Simon Club to recognize “an elite group of
economists and other pundits with the good sense to have publicly
advocated having more children.” Bryan is definitely a member, if he
chooses to accept, and just so we’re crystal clear: I advocate having
more children. Parenthood probably isn’t for everyone, and indeed there
are probably a lot of people who are perfectly happy without kids. If
you’re on the fence about having another child, whether it is your
first or your fifth, I encourage you to take the plunge. I’m pretty
sure it’s what Julian Simon would have wanted.

I joined at once.  Like Mankiw’s Pigou Club, you can join the Julian Simon Club merely by expressing agreement with the premise.  Come one, come all.