A recent study has discovered that adopted children tend to have a slightly higher IQ than their siblings who were raised by their biological parents. The difference, which equated to about 4 IQ points, appears to be the result of above average educational levels among the adoptive parents. While four points may not seem like much, it is the equivalent to moving up 10% in cognitive ability compared with the rest of the population. Study co-author Dr. Eric Turkheimer adds, “The more educated the adoptive parents are, the bigger the advantage for the child.” Proceedings of the National Academy of Sciences, March 2015