As mothers societal role has changed so much over 65 years, lack of maternal safeguards such as emotional support, Mom at home lunchtime, Mom's availability, Mom's daily full day availability could be the determining factor as children are being pushed off on schools and day care to fulfill that support role.  Perhaps Mom at home has a higher degree of emotional support in young children than we give it credit. We know after 6 yrs old male children benefit greatly from father role.  Nurture and emotional security. Is it comparable Mom's wages brought to family and the high costs of crime, anti social behavior attributed to children of working mothers.