What I remember was that he had a higher college GPA...
He did, but they also both took military officer aptitude tests, which are essentially IQ tests. Bush took the Air Force one, Kerry took the Navy one- so you can't compare scores directly- but it's most likely that Bush had a slightly higher IQ.
I wrote an article for h+ predicting that the rapid fall in the cost of gene sequencing will allow U.S. voters to learn much about presidential candidates' DNA. The candidates won't be able to stop this because:
DNA analysis has a decent chance of reducing political bias by providing objective information about candidates. If, for example, 70% of the variation in human intelligence is determined by identified genes then DNA analysis would reduce disagreements among informed voters over a candidate's intelligence.