Cara Palladino and Isabelle Barker lived in Massachusetts when they got married in 2005 and moved to the Philadelphia area later that year to work at Bryn Mawr College. They had a son in January 2009.
The couple sued the state Thursday, naming Gov. Tom Corbett and Attorney General Kathleen Kane as defendants. Their federal lawsuit seeks to declare unconstitutional the Pennsylvania statute barring recognition of same-sex marriages.
It's at least the fourth lawsuit regarding gay marriage pending in Pennsylvania.
Thirty-seven states, including Pennsylvania, do not recognize gay marriages performed legally in other jurisdictions.
Pennsylvania is the only one in the northeastern U.S. without same-sex marriage or civil unions. A law in the state defines marriage as the union of "one man and one woman."
On Wednesday, 21 same-sex couples sued in state court to overturn the state's ban on gay marriage. That lawsuit parallels a separate challenge filed two months ago in federal court by the American Civil Liberties Union of Pennsylvania.