Dr. Sophy Jesty, left, and Dr. Valeria Tanco of Knoxville, Tenn. are part of a group that filed a lawsuit to force Tennessee to recognize same-sex marriages from other states where it is legal. Shelley Mays/The Tennessean/AP

A federal judge ruled Friday that Tennessee must recognize the marriages of three same-sex couples while their lawsuit against the state works its way through the court system. There are currently 28 states facing legal challenges for their bans on same-sex marriage.

U.S. District Judge Aleta Trauger issued a preliminary injunction barring Tennessee from enforcing state laws that prohibit recognition of the marriages. Trauger noted in a written memorandum that her order only applied to the three couples.

A preliminary injunction can only be granted in cases that the judge believes the plaintiff will likely win.

The couples were legally married in other states. They filed a lawsuit challenging Tennessee's laws that prohibit recognition of their marriages. In Tennessee, marriage between partners of the same sex is prohibited by state law and by a constitutional amendment approved in 2006.

"Yet another federal judge has recognized that bans on marriage equality don't hold up to even basic constitutional scrutiny,” said Chad Griffin, president of Human Rights Campaign (HRC), a large U.S. organization advocating for the rights of lesbian, gay, bisexual and transgendered (LGBT) people.

"Though today's ruling comes from Tennessee, it joins others issued recently in Virginia, Kentucky, Texas, Ohio, Oklahoma and Utah, and in this case the judge boldly noted that it won't be long before each and every remaining ban on marriage equality becomes a footnote in history. That day isn't here yet, but today Tennessee brought us one step closer to that goal."

Currently, same-sex couples can legally marry in 17 states and the District of Columbia. Twenty-nine states have constitutional amendments that prohibit same-sex marriage. The remaining states do not have a law restricting or granting same-sex marriage.

Tennessee is just one of several states involved in litigation from same-sex couples challenging bans on marriage after the Supreme Court ruled last year that the federal government must recognize same-sex marriages.

At an HRC gala in New York last month, Attorney General Eric Holder announced the Justice Department would extend the same legal rights to same-sex couples that heterosexual couples have.

The IRS announced last year that gay couples would be afforded equal tax privileges, and the Defense Department has extended spousal benefits to same sex couples, among other federal agencies expanding the rights of gay couples following the Supreme Court’s ruling.

The White House announced on Friday that same-sex couples would be allowed the same health-care coverage as heterosexual couples through the Affordable Care Act starting in 2015.

Also on Friday, a South Carolina woman filed a lawsuit challenging the state's ban on same-sex marriage. In the case filed in Greenville County, Cathy Swicegood of Mauldin says she wants a divorce from her partner of more than a decade. However, she can’t be granted a divorce until the state recognizes her marriage.

South Carolina passed a law banning same-sex marriage in 1996, and voters passed a similar constitutional amendment in 2006.

Bans on same-sex marriage have already been overturned by federal judges in Kentucky, Nevada, Ohio, Oklahoma, Texas, Utah and Virginia. All of the states have filed appeals, which may land the cases back in the U.S. Supreme Court.

Dexter Mullins contributed to this report. Al Jazeera and wire services.