Last month, Gansler wrote that state agencies must recognize out-of-state gay marriages, until the courts or the legislature decides otherwise.
The attorney general's opinion is not itself a law, but it does guide state agencies, and it may be persuasive to the higher courts.
In recent years, the state has decided to extend a variety of protections to same-sex couples, but it has stopped short of legalizing marriages of civil unions.
Maryland law currently defines marriage as a union between a man and a woman.