The journal ''Intelligence'' published a journal article entitled ''IQ and fertility: A cross-national study'' and its abstract 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>[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, Intelligence, Volume 36, Issue 2, March–April 2008, Pages 109-111</ref> | The journal ''Intelligence'' published a journal article entitled ''IQ and fertility: A cross-national study'' and its abstract 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>[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, Intelligence, Volume 36, Issue 2, March–April 2008, Pages 109-111</ref> |