Bryan Caplan brings up some solid points in his post, “Where are the Pro-Life Utilitarians?” I still am inclined to feel that abortions are ethically permissible the majority of the time, but I obviously need to formalize my intuitions, look more closely at this, and possibly change my position if the cost-benefit analysis is clear enough.
However, I am currently ready to face a generally unpopular idea among utilitarians: “we have a moral duty to have lots of babies”. Insofar as a baby is expected to grow up and have a net-positive life, naive felicific calculus says that all things being equal, it’s better to bring this child into the world than not.
If humans reliably had lives which were overwhelmingly worth living, this would be even more clear. However, I think that current average welfare falls a good bit short of overwhelmingly worth living, so the felicific calculus is not as easy. Another variable for deciding whether or not to bring a child into the world is their expected impact on the welfare of other beings.
More people do constitute a drain on relatively finite resources, but they also statistically serve in net-positive ways in the economy. Additionally, this holds true for k and k+1 people; as society grows larger, there exists even more goods producers, idea miners, and service providers. A society with 8 billion people can produce a wider variety and quantity of goods for human welfare and increase the rate of technological and idea development more than a society of 1 billion people, so long as resources key to human welfare are not limited.
If I were to have 8 kids and could invest in all of them enough to make them average at least 1/8th as net-impactful as 1 kid I could counterfactually raise, and they are expected to have net-positive welfare over their lives, then I can see the argument that I ought to raise all of them.
The key question then is: will my nth kid have net-positive welfare and will their positive impact on society outpace their cost, such as by marginally hastening global warming at an irredeemable rate?
Their well-being largely depends on the genetics of me and my partner, as well as their upbringing. Given these factors, I think it is safe to say their life is very likely to be overall worth living. That is to say, even after having acknowledged an evolution-derived bias towards living, they would still impartially rate their life as net-worth living for qualia reasons alone.
Will they have a net positive effect on society? While I admit I have not irrefutably backed up that the average person is of net-benefit to society right now, I believe that my kids will be predisposed for above average impact/productivity. Importantly, they will also grow up in a household which values utilitarian principles so they will, in theory, be more likely to explicitly pursue high-impact activities.
I still have a lot more felicific calculus to do, but it seems to me preliminarily that many people, including many extra-conscientious, extra-happy individuals, do in fact have a moral duty to have children for the benefit of their children and everyone else in society.
If I made a jump so far in my felicific calculus that was uncalled for, please let me know.