The same gene that affects a rodent's ability to mate for life may affect human marriages, Swedish and U.S. researchers reported on Tuesday. Men carrying a common variation of gene involved in brain signaling were more likely to be in unhappy marriages than men with the other version, the team at the Karolinska Institute found. Although they are not sure what the genetic changes do to a man's behavior, some other research suggests it has to do with the ability to communicate and empathize, the team reported in the Proceedings of the National Academy of Sciences. "We never looked at...