The point I'm trying to get across is that I feel there's a limit to how much you "should" value your own child over other children, and your original post ignored this.

I would not kidnap a strange child and kill her for her kidney in order to save the life of my child. SO in that sense my own moral sentiments respect significant limits on the lives of others over my own children.

But given a chance to save my child vs save a bus going over a cliff I'd save my child.

At a sort of deep level I don't even care if it makes sense. It arises from feelings bred into my brain for 10s or 100s of millions of years before a human neocortex was even a twinkle in the flying spaghetti monster's eye.