Between 1968 and 2017, the share of families with children younger than 18 headed by a single mother increased from 12 to 21 percent. An additional 4 percent of families are headed by a single father.

Meanwhile, according to a 2015 survey by AARP and the National Alliance for Caregiving, approximately 34.2 million Americans, or 14.3 percent, provided unpaid care to an adult age 50 or older.

These are just a few statistics revealing how family caregiving responsibilities are varied but shared by millions of Americans. For those balancing caregiving responsibilities with work, family and medical leave policies play a critical role.

I recently testified before the US House of Representatives Committee on Education and Labor Subcommittee on Worker Protections on how family and medical leave supports workers in many ways. My testimony highlighted four considerations for policymakers as they chart the future of these protections.

1.  Our policies should adapt to changing family and household dynamics and demographics

The 1993 Family and Medical Leave Act (FMLA) had important positive effects on families and workers, with minimal evidence of negative consequences for business or economic growth. However, family earnings dynamics, caregiving needs, and the structure of the labor market have evolved in the past quarter-century and demand policies and protections beyond those afforded by the FMLA.

Women now play an equally important role as family breadwinners as they do as family caregivers. Indeed, as of 2017, 41 percent of mothers were the sole or primary earners for their families, earning at least half of their household’s total earnings.

Family caregiving needs extend beyond parents caring for a new baby, especially as Americans get older. The sheer number of baby boomers means the number of elderly people grows annually, and the fastest growing group of older adults are those ages 80 and older.

The structure of work is shifting. Although still a relatively small share of the overall labor force, alternative work arrangements accounted for 94 percent of employment growth between 2005 and 2014.

2. The most vulnerable often can't access FMLA protections.

The FMLA provides important protections for families balancing work and care responsibilities, but the most economically vulnerable workers too often are excluded from accessing these rights.

More than 14 million workers took FMLA leaves in 2012, the most recent year for which we have available data from the Bureau of Labor Statistics. However, many more workers are unable to take leave for family or medical reasons without risking job loss. Forty-four percent (PDF) of the workforce is not covered by the FMLA. The FMLA currently excludes part-time workers, including those who work a full-time schedule split across multiple employers.

There are substantial demographic disparities in worker access to FMLA-protected leave. For example (PDF):

• For working women of childbearing age, 42.6 percent are not eligible for FMLA protection.
• Less than half of all workers living in families with incomes under $40,000 are FMLA eligible.
• Hispanic and non-white workers are less likely than white workers to be FMLA eligible.

Given the FMLA’s limits, it is not surprising that unmet demand for needed leave is high. Sixteen percent of workers report a time when they needed to take time off for an FMLA-qualifying reason but were unable to. Nearly a third of workers in low-income households were not able to take needed leave.

3. Modernizing the FMLA would expand access to leave for millions of workers who need it.

Updating the FMLA to protect part-time workers could help millions of families.

The FMLA’s definition of “family” is also limited and as such does not include the most important caregiving relationships for many workers.

For example, the FLMA does not offer protection for grandparent caregivers. Nearly one million grandparents serve as their grandchildren’s primary caregiver, and more than half of these grandparents were in the labor force.  Updating the definition of  "family" to reflect the multigenerational households of contemporary America would expand access to leave.

4. Job protection and wage replacement are central concerns.

Job protection is one of many important elements that Congress ought to consider when designing effective family and medical leave policy. Wage replacement is another.

An increasing number of states have implemented paid leave programs that allow workers to earn paid time off for parental, family, and medical leave. All the state programs use a social insurance model, in which time off is funded by a very small payroll contribution. Many of those states have combined those paid leave policies with rights to job protection that go beyond those provided by federal law.

Evidence tells us these policies can have wide-ranging positive effects on child and adult health, as well as on earnings and employment outcomes for leave takers.

Because labor force participation rates are critical to economic growth, policies that boost labor force attachment, like paid leave, are a macroeconomic growth strategy, and a support for working families.

Businesses in states with paid family and medical leave programs view these policies favorably (PDF). Paid leave programs may also improve productivity by reducing turnover.

While states have provided models for what works, the evidence suggests that the time has come for updating federal policy to meet the challenges of the 21st-century economy.

A federal program with uniform eligibility requirements, protections, and benefit schedules would eliminate a patchwork of laws that lead to disparate impacts , and create a level playing field for state finances, employers, and  workers. A federally administered system coupled with federal protections would be substantially more efficient to administer than 50-plus separate state and local programs.

In conclusion, the evidence tells us working families are facing substantial challenges to meeting both their economic and caregiving responsibilities. But research also tells us we have policy solutions available—solutions that work for workers,  families, employers, and the economy as a whole.