It’s difficult to say but it’s a brilliant analogy to highlight the limits of morality where it claims to increase human happiness –rather than pay for your child’s (non life threatening) healthcare, surely you’d distribute it to those whom are starving etc, for example. Of course people don’t do this and it doesn’t necessarily make them immoral, rather people often make grandiose claims of their morality.
It hints at the basis of all empathy and all morality which originally evolved through mutual gain and reciprocation, when humans lived in communities with their close relatives. This would perpetuate the very genes (as many genes are shared with offspring, siblings etc) that caused that behaviour in the first place and on it goes!
We don’t live in completely moral societies of course because a good amount of genes which encourage us to ‘cheat’ the system and exploit kindness are also at an advantage some of the time! 🙂