Children

Why should we have more children?
The answer I have recently been giving, is that there is every reason not to and that is the strongest argument for.
So certainly it says it in the Torah, Pru u'Rvu. But why does the Torah say that?
And asking the question in light of a world population boom, the Torah's words are timeless not only for the olden days when there weren't that many people around.
Simply put it is a Mitzvah for Yidden (interesting that the mitzva is basically only two children but they have to have children. In light of statistics we know that on average one needs to have 2.1 children for society to stay the same. And taking into account having grandchildren, takes care of the concern for the point 1 for cases of infant mortality etc. But that still isn't multiplying that's just treading water?).
We need more Yidden and not just in context of the holocaust. And not just because we give charity at higher percentage and therefore it is better for the world if there are more Yidden.
But especially because Yidden doing Mitzvos will make it a better world for them. Through Ruchnius and through them seeing how one should live their lives. And certainly then this imperative is incumbent especially on frum Yidden and especially Chassidim and especially Shluchim where we can live a life of self-sacrifice as a lesson for all to see.