There are many ways in which a child can be raised in an atypical household. In this context, 'atypical' would be anything that isn't the nuclear family which is the familiar unit consisting of two parents and their children. This includes anything from being raised by a single mother, a single father and even parents of the same sex. It wasn't surprising to me that being raised in a household with parents of the same sex did not impact a child's development. Especially since each person in most same-sex couples still contributes to different aspects of parenting just as they would if they were both of the opposite sex. I was surprised to read that the children of widows showed no higher rates of developmental problems than children from two-parent households, even though children of mothers who have been divorced, or separated, do. 
Whether this is causal or correlational cannot be determined. One reason that I believe this may be the case, though, is because some couples that divorce or separate have familiar troubles long before the separation. This, in turn, may affect the child's behavior by viewing the parents'. My biggest question in this matter is whether or not the influence of having a "nontraditional" family plays a correlational role or causative role in the child's development. Are parents that have had or do have emotional or behavioral problems more like to divorce, therefore passing those genes on to their kids? Or does the divorce, itself, cause the child to display those problems?
