A federal judge declared Pennsylvania's ban on gay marriage unconstitutional Tuesday.
Several couples sued the state in July for the right to marry in Pennsylvania or to have their out-of-state same-sex marriages recognized. A 1996 state law defines marriage as a union between a man and a woman.
The state's Democratic attorney general, Kathleen Kane, had declined to defend the law in court. GOP Gov. Tom Corbin took up the case, however, with lawyers for his administration arguing that states have the right to determine the definition of marriage.
On Monday, a federal judge in Oregon overturned Oregon's ban on same-sex marriage. State officials there also declined to defend a ban, citing last year's U.S. Supreme Court ruling that tossed out key parts of the federal Defense of Marriage Act.
Judges have tossed out similar bans in a half dozen states since the Supreme Court decision.
The Pennsylvania lawsuit, filed by the state American Civil Liberties Union, claimed the state's own Defense of Marriage Act and its refusal to marry lesbian and gay couples or recognize their out-of-state marriages violates the fundamental right to marry -- and, by discriminating based on sexual orientation, the Equal Protection Clause of the Fourteenth Amendment.