Foreign Aid takes 0.7 of the national budget, any cut will have an insignificant effect on the national Debt, so why bother? It should be left as it is.
Very little of the money goes direct to freign government, it is usually tied to specific projects and monitored.
Of course someof it goes astray. Money goes astray in the UK as well; wasteful projects corruption in local and national governement.
On birth control, in the majority of countries in the world the birthrate is around replacement level already. It is those at the other end of life that are the cause of increasing world population.
Us oldies are living far longer than we used to do and with a standard number of births coming on, population will continue to grow until growth in life expectancy stabilises.