pronatalist
/(ˌ)prəʊˈneɪt(ə)lɪst/ /(ˌ)prəʊˈneɪtəlɪst/noun
A supporter of pronatalism; an advocate of the practice of having a large family.
adjective
Of or relating to the encouragement, especially by the State, of the practice of having a large family; in favour of or advocating large families.
Origin
1930s; earliest use found in Modern Law Review. From pro- + natal + -ist, perhaps after French, although this has not been traced.