Largely as a result of revived interest in this case following Gordon-Reed's book, a Y-DNA analysis of Carr, Jefferson and Hemings descendants was conducted in 1998. Y-DNA is passed on virtually unchanged through the direct male line. It showed no match between the Carr male line, proposed for more than 150 years as the father(s), and the one Hemings descendant tested. It did show a match between the Y-DNA haplotype of the Jefferson male line and the Hemings descendant, which is a rare type.