The U.S. is the only wealthy country in the world that doesn’t guarantee workers a single day of paid leave.

One finding in the Urban Institute’s report: Less than half of women 18-34 get paid parental leave, even though they’re the demographic most likely to have children.

Opposition to paid leave has often been rooted in the challenge it poses to businesses. That calculus is changing.

U.S. federal law requires companies to give workers 12 weeks off a year for family medical situations — unpaid. Whether or not workers get paid leave depends on what state they live in.

But they may not get to those who need them most.