Why do some people think it's impossible to love and care for a child that is not biologically their own?

Mm I don't know. Maybe they feel that if they don't go through the bonding experience when the child is born that they can't connect with it. There are countless of people who do have children who aren't biologically theirs and they say they love them like their own. I dunno it's funny though because there are people who love their pets as if they were humans, and obviously they aren't the biologically parent.lol