February 19th, 2020

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Mechanisms of Twinning: XI. Do Mothers of Twins Have Higher IQs? The IGF Connection
Authors:  Gary Steinman, M.D., Ph.D.
  OBJECTIVE: Based on prior studies of the roles of insulin-like growth factor in twinning and in cognitive function, it was the purpose of this project to determine if there was a relationship between the production of twin gestations and maternal intelligence quotient (IQ).

STUDY DESIGN: A statistical study was performed using the occurrence of twinning and intelligence quotients reported by mothers who had conceived twins without assisted fertility means applied.

RESULTS: Whereas the national IQ average in the United States has been reported as 98, the mean score of 72 mothers of twins who participated in this study was 131.

CONCLUSION: A parallel relationship was documented with this survey of mothers of twins and their IQs. It was concluded that this supported the proposal concerning the common role played by insulin-like growth factor in both functions in women.
Keywords:  heritability, insulin-like growth factor, intelligence quotient, twinning, twins
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