Whilst I don't blame the children, by saying nothing I'm encouraging it to happen repeatedly. Sure, itd be harsh for a few years, but if you or I or anyone else who isnt a dole addict gets the dick wet (with consequences) we've to work to pay for our kids.
Simply disallow payments for more than the first child, everyone is allowed a mistake/accident/I was drunk and didn't pull out in time, but lets not encourage "dolers" to have MOAR kids (which they most likely wont look after properly)just for the extra scrilla.