It has to be a leftist position. Social systems don't work with inflows of people that take out of the system without paying in. It's rational to protect the system from collapsing. Problem these days is, rationality is not existent anymore.
Discussion
What the fuck are you talking about?
The issue here was immigration, not childbirth
Leftists believe the state has to take care of the population. So you will have rational positions on the left that consider how to actually finance that without going deeper and deeper into debt, or you will have ideologist positions that believe money grows on trees and paying for everyone coming to the system doesnt cause issues.
Sane people don't care about whatever you're talking about
Let people walk places, give them food if they're hungry, try to grow enough food, expect people to die because we've already not been doing the food growing step for a long time
There's no math, it's very simple