There are many studies of twins, including a comprehensive study at the University of Minnesota by Dr. Thomas J. Bouchard Jr. that received worldwide attention. The study showed that the IQs of identical twins raised apart were
much closer than random adopted children, and that they were even closer than for fraternal twins who were raised in
the same home, and who attended the same schools. Not a single twin study has ever contradicted these results. [46] [47]
Let me emphasize this important point - identical twins growing up in completely different environments - with
different parents, different schools, different diets, different political and religious persuasions - have IQs closer
together than those of fraternal twins raised in the same family. If intelligence is primarily created by environmental
factors, certainly the fraternal twins raised together in the same familial, social, and educational environment should
obviously have much closer IQs than twins who were raised apart.

My Awakening - David Duke