ANNAPOLIS, Md.—Unmarried couples would get additional medical decision-making rights in Maryland under a bill headed to the governor.

The House of Delegates has approved a bill to allow domestic partners, who could be gay or straight, to make medical or funeral decisions for each other if they meet certain criteria to show they are a committed couple.

The bill has already passed the Maryland Senate and is now headed to Gov. Martin O’Malley to be signed.

Some Republicans in both chambers tried to defeat the decision-making bill, saying it paves the way for gay marriage. But supporters said gay couples should be allowed such rights as riding in ambulances with a sick partner or making next-of-kin funeral decisions.