1. I have no figures on subsidies for child-rearing, but "heavily subsidises" seems very unlikely in most places, maybe Scandinavia can make that claim. I suspect any help provided by the government is more than wiped out by lost income from one parent staying at home or working part time for ~5 years (or more with multiple children). Or nursery costs should both parents want to work as soon as possible.

2. Donating to Doctors Without Borders is just enabling someone else to do a good deed, the donator has zero responsibility. Parents are legally required to look after a child for 16 (i think, in most countries) years.

3. The world population won't keep growing, fertility rates are only above 3 in Africa. Other "developing" countries are on course for the population to stabilise, western developed countries will see population dropping. Google tells me 2064 for current projected population peak.