As far as dysgenic fertility (people with lower intelligence having more children) and its effect on population's intelligence, the abstract for journal article ''IQ and fertility: A cross-national study'' published in the journal ''Intelligence'' states: "Many studies have found a small to moderate negative correlation between IQ and fertility rates. However, these studies have been limited to the United States and some European countries. The present study was a between-nation study using national IQ scores and national fertility rates. There were strong negative correlations found between national IQ and three national indicators of fertility."<ref>Abstract for journal article ''Intelligence'', [https://www.sciencedirect.com/science/article/abs/pii/S0160289607000244#:~:text=Numerous%20studies%20have%20confirmed%20that,with%20higher%20levels%20of%20IQ. IQ and fertility: A cross-national study] by Steven M. Shatz, Volume 36, Issue 2, March–April 2008, Pages 109-111</ref> | As far as dysgenic fertility (people with lower intelligence having more children) and its effect on population's intelligence, the abstract for journal article ''IQ and fertility: A cross-national study'' published in the journal ''Intelligence'' states: "Many studies have found a small to moderate negative correlation between IQ and fertility rates. However, these studies have been limited to the United States and some European countries. The present study was a between-nation study using national IQ scores and national fertility rates. There were strong negative correlations found between national IQ and three national indicators of fertility."<ref>Abstract for journal article ''Intelligence'', [https://www.sciencedirect.com/science/article/abs/pii/S0160289607000244#:~:text=Numerous%20studies%20have%20confirmed%20that,with%20higher%20levels%20of%20IQ. IQ and fertility: A cross-national study] by Steven M. Shatz, Volume 36, Issue 2, March–April 2008, Pages 109-111</ref> |