When is it appropriate to fight in front of the kids?  In John Medina's book Brain Rules (Updated and Expanded), he talks about "One of the greatest predictors of performance in school turns out to be the emotional stability of the home... Given that stress can powerfully affect learning, one might predict that children living in high-anxiety households would not perform as well academically as kids living in more nurturing households. That is exactly what studies show. Marital stress at home can negatively affect academic performance in almost every way measurable, and at nearly any age...