Hopefully we're now going to see his reaction to realising what bringing children into the world means.
What would it be?
He is already mentally ready for it, and is preparing for it to begin with as well.
From your wording, it feels like you want MC to go through some existential crisis on learning about having babies and starts to blame himself for doing it without thought or something.
But as mentioned in the plot, except the first few when he didn't understand how his powers worked, he has been ready to take responsibility for all of them. Especially when he plans to take advantage of the system to increase his own strength (for an adventurer, strength is proportional to income).
Plus, I am sure that majority of the girls aren't really going to hold MC accountable for impregnating them, especially the prostitutes that had been arranged by his Onee-san.
It's easily possible that out of the 12 girls MC had impregnated until now
[9 prostitutes (including his Onee-san), 2 normal girls (his friend and the former princess), and 1 unknown], MC would obviously take responsibility for his loved one, his Onee-san and the Tan-skin prostitute, not sure about the former princess though, and can't say much on the unknown one.
As for remaining prostitutes, i would say that about 2 of them might ask him to take responsibility for the child, while the remaining 5 probably won't ask (like the Halfling girl is almost confirmed to not ask for MC to take responsibility, as she already had plans to move to her hometown as soon as she got impregnated by any human man).
