Nine women can already have babies in parallel. That is, nine women cannot have a baby in one month, but nine women can have nine babies in nine months.

It would probably be more practical to make old age less expensive than to inject more people into the bottom of the demographic pyramid. Those young people eventually get old too. I am looking forward to my sentient robot caretaker:

“Open the refrigerator door, HAL”

“I can’t do that right now”

Once we ditch our centrally controlled economies perhaps life can be affordable enough to not prevent willing parents from having children.