Scientists from the Research Institute of McGill University Health Center published an article in the journal, Cerebral Cortex, in December of 2013 showing that the absence of the father during critical growth periods leads to impaired social and behavioral defects in mice. Surprisingly, mice are ideal for a study like this because they are raised by monogamous partners much like humans. It is also practical because it only takes a few weeks in mice (because of their short life span) and in humans it could take decades. It would still be best to do a human study.
Researchers compared the social behavior and brain anatomy (the prefrontal cortex) in mice reared by both parents and those reared only by the mother. They found defects in the prefrontal cortex, the place where social and cognitive behavior are managed.
In today's world where 50% of the population will eventially get a divorce, there are a myriad of ways kids are raised, and often without a father. This study confirms what we always suspected: we need both a healthy father and mother to grow up well adjusted!