The shift away from defined benefit pension plans to defined contribution plans has affected the types of retirement benefits available to most households, but has negatively impacted women the most, particularly those who are not married, according to a report by the Government Accountability Office.

Since the 1960s, the percentage of unmarried, single-parent families has risen dramatically, especially among low-income, less-educated individuals and some minorities, the report found. At the same time, the number of women in the labor force has increased. Both of these events have affected the types of Social Security benefits households receive, with fewer women receiving spousal benefits today than in the past.

The shift from DB to DC also has increased financial vulnerabilities for some of these same groups because DC plans offer fewer spousal protections.