In a game theory setting, i.e. highly constrained and not tainted by that annoyingly complex and unintuitive stuff that is reality, you'd be correct. It also i

In a game theory setting, i.e. highly constrained and not tainted by that annoyingly complex and unintuitive stuff that is reality, you'd be correct. It also ignores the fact that the vast majority of people don't make new humans as a selfless public service, thus "selfish" takes on a new definition which can be translated as "doing what people do", at which point it loses all meaning. In poor countries making new humans is a necessity, in rich countries it's a natural desire, and in all cases it's a fundamental human right even if the offspring take more than they give as everyone is a product of circumstance. Exercising the option to not make any is equally valid.