“Evidence of Dysgenic Fertility in China”, Mingrui Wang, John Fuerst, Jianjun Ren2016-07 (dysgenics)⁠:

The relationship between fertility, intelligence, and education was examined in China using a large sample sourced from the population-representative China Family Panel Studies (CFPS) dataset.

For the 1951^–₁₉1970_54ya birth cohort, the correlation between fertility and gf was −0.10. The strength of recent selection against g_f in China substantially increased between the 1960s and the mid-1980s. Later (1986^–₁₄2000_24ya), the speed of decline in g_f due to selection stabilized at about 0.31 points per decade with a slightly downward trend. The total loss 1971 → 2000 due to dysgenic fertility is estimated to be 0.75 points.

A negative relationship between educational attainment and fertility was additionally found. Both negative relations were stronger for women.