Owl, I don't know where to start in response to your post, the level of ignorance should shock me but sadly it doesn't. I sincerely hope you are never in a less than ideal situation through no fault of your own. Even the most rich and successful amongst us are only ever 3 steps from the gutter.
What would it take for you - a sudden illness, unexpected redundancy, marriage breakdown. Maybe a combination of all three but don't ever be so completely sure it couldn't happen.
This particular thread is about parents who are healthy enough to work being paid to stay at home with their child. Therefore the above argument is completely irrelevant.
Illness, redundancy or divorce are not going to make me expect to stay at home with my own children at the expense of the state. I'm not saying I'm guaranteed to never be in a position to need JSA, or disability benefits, and both of those things are actually benefits that I think should be more generous.
But I can guarantee that I will never leave a job because I am pregnant, and that I will never conceive while both myself and my partner are out of work, and that I will never claim child tax credits or income support to enable me to stay at home just because I chose to have a child. There is a very tiny possibility that I might find myself needing to claim help with childcare, although it's highly unlikely, but that's really not the same thing.
I see no problem with expecting people to contribute to society while they are claiming benefits and are healthy enough to work. I don't think people should be made to leave worthwhile voluntary positions to do mandatory work experience, because those people are doing something to help their CV and gain experience and are contributing. But I think people are kidding themselves when they think they are contributing to society by sitting on benefits to look after their own children.