Suppose you are an anti-natalist, what does efficent charity look like then? What is the most cost effective way to reduce the number of births? I imagine giving out cheap birth control in places undergoing a demographic transition is pretty ok?
straight number of births isn't the right metric you need number of births times misery per birth minus opportunity cost of one less person
See, e.g. Population Services International.
Some quotes from their web site:
...The mission of PSI is to measurably improve the health of poor and vulnerable people in the developing world, principally through social marketing of family planning and health products and services, and health communications.
In 2009 alone, PSI prevented an estimated 3.5 million unintended pregnancies and over 17,000 maternal deaths, and enabled millions of couples to plan their families.
Over the past three decades, PSI has expanded the contraceptive methods in its portfolio from
If it's worth saying, but not worth its own post, even in Discussion, it goes here.