A 20-year (1980-2000) longitudinal study of Marital Instability Over the Life Course found that having grandparents who divorced was associated with having a lower level of educational attainment, a greater likelihood of marital discord, and a poorer quality of parent-child relationship. This association held even if the grandparents' divorce occurred before the grandchild was born.
Source: "The Long Reach of Divorce: Divorce and Child Well-Being Across Three Generations", Amato, Paul R., Cheadle, Jacob, Journal of Marriage and Family Vol. 67, Number 1. February, 2005. Page(s) 191-206.
(HT: FamilyFacts.org)
I'd say that this speaks to the pervasive nature of broken marriage. I never realized that statistics bear out the sins of the father being revisited on the sons.