I believe that the existing welfare state and benefits system addresses these matters enough without putting an extra burden into the equation.
What actually makes a difference to a child's future is good parenting and education.
Historically, children nowadays are more well off than they have ever been, yet there levels of social problems and youth offending are higher than ever. Being poor as a child does not mean that you will turn out to be bad, ignorant, ill or that your life is doomed.