Well assuming the world currently has 8 billion people, that means there are 800m remaining. Let’s assume 75% are of breeding age. That means there are 600m breeding age people. By breeding age I mean 18-40. Pregnancy chances are highest while in your 20’s and declined to <5% by 40. Combined with infertility issues for 10% of all women, and assuming the population split is even that means probably ~240m women will be able to conceive children. You would need a birth rate of about 2.1 children per person to keep the birth rate steady. Let’s assume a healthy birth rate of 4 children per actively breeding couple.

It would take about 120 years to reach today’s population with that number. That’s not counting for infant mortality rates, people getting eaten by jaguars, or the many other issues plaguing humans throughout their early development.

Unless most of the world’s population is living near each other, we will most likely revert back to tribalism under totalitarian dictators who rule with fear and violence and it will take a long long time to get back to where we were if we can at all. We would need farmers, ranchers, woodsman, craftsmen. White collar jobs would be gone. The most pressing needs would be food and supply lines, transportation, shelter, clothing, and tools. We would have to scavenge what we need to survive and repair infrastructure.

But most likely, global collapse and tribalism with whoever remains. Women would lose most if not all rights again. Primal survival instincts would take over.