Yes, but they do it in order to fill up a hole in their lives, to have a “greater purpose”, give their lives meaning. Ultimately all we do is to satisfy our desires…and the push towards caring for kids is one of the biologically hardwired desires we evolved having, the reason we do it is not really a lack of ego. Having a family is something people want for themselves, for their own happiness.

I believe it’s literally impossible for a person to not be egoistic without going crazy and/or offing oneself. Even christians who preach about self sacrifice and generosity only do it pushed by the promise of a better afterlife and their own self-interest of wanting to avoid hell and/or being closer to their god.