Many countries are trying hard to encourage people to have more children. Poland has drastically increased its monthly child benefit per second and later child, and it is having some effect, though still early in the game. This income redistribution will pretty soon require massive tax increases for it to be sustainable. Sweden appears to have successfully used generous child care and parental leave programmes to raise the birth rate.  None of this can compare with the birthrate in Islamic societies and among immigrants in Europe, and this drives the sort of reactions we know rather well. Let's not forget that in Europe youth unemployment is very high, and  the employment market is very stiff, while the likelihood of large numbers of people being expelled from Britain after Brexit is quite high.