U.S. households’ retirement difficulties are exacerbated by social inequality, according to a recent report, especially gender inequality—but improving retirement plan design could provide a partial solution.

Currently, women constitute 47% of the U.S. workforce, and 40% of working women are in managerial and professional positions, according to the report. That represents significant progress since 1975, when just 18 percent of working women were in managerial or professional jobs.

Yet a significant earnings gap between men and women persists. In the U.S., an average working woman earns 21 percent less than an average working man. While a portion of this earnings gap is caused by different career and lifestyle choices between men and women, gender discrimination still sandbags women’s ability to earn an income and thrive during their working years.

The gender earnings gap has implications for women as they age. For example, the average woman qualifies for Social Security benefits 23% lower than the average man. Click here to read more.