Women with IQs of 120 and up have the fewest children today ,perhaps because women's liberation has given us other possibilities. At Berzerkeley , abortions were free on campus and many of my classmates, future chemists , brain surgeons etc had abortions.Poor people don't worry about the cost of raising children because they are taken care of by our welfare state whereas educated professionals limit the number of children they have because they pay for them.Nothing is expensive if someone else is paying for it.We might increase the birth rate among 120 IQ women by offering better tax incentives for having children.
In many countries , birth control is free and available to teenagers and if we had free anonymous acces to birth control here , the teen birth rate here would go down and so would the birth rate to women with the lowest IQs.