If I have to choose between the good of the "Jewish people", or the good of "the world" - neither of which have any ultimate existence, both are constructs in "my head"- then it seems I choose the good of "the world".
The good of the Jewish people is for us to have another child, perhaps to "make up" for (as if that were possible) the six million slaughtered in the Shoah - the Holocaust. Perhaps to allow a soul that did not complete its mission then to reincaranate in another body and this time live and die peacefully. To "redress" the historical reversal, in that there were 18 million Jews before the war and now there are only 13 million and the population levels have never recovered from the massive amputation of the body of the nation. But all of this is thinking in abstract concepts - every life is a mracle and a universe - and the numbers game restores nothing. Even if there were 18 million identifying and creatively Jewish Jews alive today, that does not ease the suffering of those torn apart by the Shoah.
The good of the planet ( and who knows what the fuck is good for the planet, its all made up and based on unverifiable assumptions) is not to have another child. As it is the earth groans under the weight of 6 billion voracious consumers who over harvest and over exploit heedlessly and unconsciously. Every child born is the potential death of thousands of domesticated animals and thousands of non domesticated animals whose habitats are devastated by human settlement. There are more than enough parentless children on the planet - let us assume responsibility for them, rather than seeking only to perpetuate our "selves" in the narrowest understanding of that term - us as bodies and particular and particularistic stories and narratives...
So I choose not to have another child...instead someone else's child will become mine, when I nurture them in ways their biological parents could not or would not. I will be part of that village it takes to raise a child.