Anything which is aimed at financially incentivising "families" is silly IMO.
The average cost of a wedding is something like £20k. You can't apply the drone-rationality of economics to something as complicated, as supra-economical, as human, as whether or not family units will exist and remain strong.
Targetted help to ensure kids are kept out of poverty is fine but it should be in the form of children's clothes vouchers, food vouchers and heating allowances etc...