Plaintiffs Fernando Chang-Muy, center, and Len Rieser, right, of Philadelphia, listen as daughter Isabel Rieser, left, speaks during the announcement of a lawsuit seeking to overturn a 17-year-old state law effectively banning same-sex marriage in Pennsylvania.

HARRISBURG — Civil rights lawyers filed the first known legal challenge Tuesday on behalf of 23 men, women and children seeking to overturn a 17-year-old state law effectively banning same-sex marriage in Pennsylvania, the only northeastern state that doesn’t allow it or civil unions.

The lawsuit, filed in federal court in Harrisburg, also asks a federal judge to prevent state officials from stopping gay couples from getting married. It names Gov. Tom Corbett, Attorney General Kathleen Kane and three other officials.

The plaintiffs are a widow, 10 couples and one of the couples’ two teenage daughters. They include four couples who were legally married in other states but whose marriages go unrecognized by Pennsylvania.

Same-sex marriage is legal, or soon will be, in 13 states. The lawsuit seeks to legalize it in Pennsylvania and to force the state to recognize the marriages of same-sex couples who wed in other jurisdictions.

Lawyers in the case believe it is ultimately bound for the U.S. Supreme Court, probably along with similar cases that are cropping up in other states, and could force the high court to rule on the core question of whether it is unconstitutional to deny same-sex couples the right to marry.

The plaintiffs, some of whom spoke during a news conference in the state Capitol after the lawsuit was filed, said their willingness to join was driven partly by a desire to have the legal and financial protections afforded to opposite-sex couples, but mostly by the emotional satisfaction of seeking social justice.

“Everyone in our world recognizes us as a true family,” said Deb Whitewood, 45, who lives in the Pittsburgh suburb of Bridgeville with her partner of 22 years, Susan Whitewood, and their three children. “We feel that it’s time that the commonwealth of Pennsylvania did, too.”

Another couple, Dara Raspberry and Helena Miller, who were cradling Miller’s 6-week-old daughter, said they married in Connecticut before moving to Philadelphia to be closer to family. But, Raspberry said, they were forced “to become unmarried and less of a family” under Pennsylvania law.

Isabel Rieser, the 21-year-old adopted daughter of plaintiffs Len Rieser and Fernando Chang-Muy of Philadelphia, said her two fathers should be able to marry after 32 years of commitment.

“Besides, I am so over being a child out of wedlock,” Rieser joked. “I look forward to my parents finally getting married. I have so many ideas for their wedding: food, location, decorations.”