The last point is the one that I think gets almost zero attention. People talk constantly about how great and fulfilling it is to help bring a child into the world, see it grow, teach it all the things you know, etc. What they actually mean is that it's very gratifying to have kids that are yours and look like you and came from you, because deep down we are all narcissists.

When you start talking about how they could have done literally all of those things by adopting any one of the bajillion kids that need it, most people will openly tell you that they would never consider it and don't feel even slightly hypocritical about it.