Cut income tax by 5% for working parents who are British citizens

The UK birth rate is declining. I believe by cutting income tax for working parents will firstly secure British culture by reducing the dependency on foreign workers in the future, help with the cost of living helping them out of debt. I think this would help mothers back to work by giving them an incentive, and support the future of the UK economy by providing more British citizens paying into the tax system. This would only apply to British citizens.