SOUTH BEND, Ind. (AP) — More than 20 Indiana University employees will lose health care coverage if they don’t marry their same-sex partners by the end of the month.

The South Bend Tribune reports that university employees in same-sex relationships have relied on a domestic-partner health care policy offered since 2002. That benefit ends Dec. 31.

Employees who applied for the benefit were required to sign an affidavit saying he or she would marry if the opportunity was available.

A university spokeswoman says the number of domestic partners enrolled in medical plans dropped from 250 at its highest point to 22 after marriage certificates were submitted following the 2015 U.S. Supreme Court decision that legalized same-sex marriage.

The university’s human resources department has said it’ll continue to explore employee requests to expand health care coverage to all same-sex and opposite-sex domestic partners.