Marriage is not as widespread as it used to be, but it is still an ideal to which most people aspire, and it still provides the surest foundation for strong and healthy families. Something about marriage itself—perhaps the public as well as private commitment it requires or the stability it encourages—seems to encourage husbands, wives and children to support each other and work together to build lasting families whose positive contribution is felt not only by the family members, but also by the larger society.
This report by Civiitas: The Institute for the Study of Civil Society attempts to summarise a large body of evidence from social science research in the UK and elsewhere on the importance of marriage to families and to society.