How do you propose to solve the population crisis ? Given a choice people will always want the position of less responsibility. As a society we have agree to give sacrifices so that we can have next generation.
The population crisis is that the current population isn't sustainable: https://en.wikipedia.org/wiki/Earth_Overshoot_Day (and most of those haven't a rich lifestyle yet; most people on HN are in the top 10% worldwide income). We need either to become more sustainable per capita, have fewer capita, or get more earths. Any solution is fine. Otherwise, we'll run out, and the remaining 90% of people get a lot of undeserved worldsuck
Note that we are already doing what you want: world population is projected to increase by 25% (!) in the next 75 years. At the same time, we're lifting people out of poverty (https://ourworldindata.org/grapher/share-of-population-in-ex...) which causes them to be able to buy more stuff, live richer lives, and be less sustainable (e.g. visible on a CO2 chart for the same countries: https://ourworldindata.org/grapher/co-emissions-per-capita?c...). Which is fair right? Why shouldn't they get to live like us. But we can't go on like this; something has to give.
More people isn't helpful for at least another century. Let's evaluate the baby-making situation in 2100 and work on the real problems we face today
by accepting that it is unsolvable. you will not fix it with incentives, disincentives, and government-funded nagging. fixing the population crisis requires undoing urbanization and education. good luck with that.