From Science Daily.
Jard C. Roach et al., Analysis of Genetic Inheritance in a Family Quartet by Whole-Genome Sequencing. Science, 2010. Pay per view.
By comparing the parents' DNA sequences to those of their children, the researchers estimated with a high degree of certainty that each parent passes 30 mutations -- for a total of 60 -- to their offspring.
Scientists long had estimated that each parent passes 75 gene mutations to their children.
That means an effective mutation rate of just 2/5 the usual estimates.