Parents are not necessarily always there for their children. Parents die and leave their children to fend for themselves in the world.
I'm 60 years old and I could sure use my mother's help right now. But she's gone, long gone. 27 years gone. And it shook my very foundation when she died. I drowned myself in booze for about 12 years after her passing.
That's a good part of the reason I've never had children. Couldn't stand the thought of bringing a life into the world and then not being able to be with them and watch over them and protect them...always.