That'd be brilliant that. Turn everyone into accountants or perfectly logical vulcans... They'll never pop babies out until they can personally afford it. Most of them never would afford it.
Now this is the bit where I start thinking about phrases like "replacement rate", "negative population growth", "retirement homes that can't find the staff", "labour shortage", "negative economic growth", "prolonged depression", "this was a bad idea"...
I dunno, seems that if the best answer you can come up with to wages not meeting the actual cost of labour is "labourers should chop their own cost of living so harsh they can't even breed", then maybe you're not good at this sort of thing. That's actually a million times worse than just letting the welfare state carry on paying rest of the cost of labour, and completely unimplementable anyway.