House Democrats are pushing for inclusion of gay families in immigration reform.

On Thursday, a coalition of 37 groups joined members of Congress in urging passage of the Uniting American Families Act (UAFA) this year as part of a comprehensive immigration reform package.

The UAFA would allow gay Americans to sponsor an immigrant partner for citizenship.

“Couples who are in love, who are committed, who are married, should not be separated; one in this country, the other in that country,” New York Congressman Jerrold Nadler said at the news conference on Capitol Hill. “No immigration reform measure will truly be deserving of the term 'comprehensive' unless it provides equality for gays and lesbians as well.”

“Every day that Congress fails to take action, American families are separated or forced into exile, including more than 17,000 families raising young children,” Rachel B. Tiven, executive director of Immigration Equality, a group that lobbies on behalf of gay immigrants, said. “For those families, and their loved ones, today's clear call to action, from key Congressional champions, could not be more welcome or more timely.”

Openly gay Colorado Congressman Jared Polis said the country's immigration system “contains laws that discriminate against LGBT families.”

“To be truly comprehensive and achieve real, long-lasting reform, we must provide all domestic partners and married couples the same rights and obligations in any immigration legislation,” he said.

Currently, the Defense of Marriage Act (DOMA) forbids any federal agency from recognizing married gay couples.

Opponents of gay-inclusive immigration reform say it's a back door to gay marriage.

“It tries to redefine traditional marriage. I can't support that,” Utah Representative Jason Chaffetz told Fox News.

Socially conservative immigration reform allies also oppose inclusion of the UAFA.

In tucking the UAFA last year into his legislation, the Reuniting Families Act, California Representative Michael Honda angered conservatives, and drove one major partner to withdraw its support.

In a letter sent to Honda, the United States Conference of Catholic Bishops, a major ally in securing immigration reform, called the gay provisions “contrary” to its position on marriage.

“[Including the gay provisions in the immigration bill] would erode the institution of marriage and family by according marriage like benefits to same-sex relationships, a position that is contrary to the very nature of marriage, which pre-dates the church and the state,” the bishops wrote.

Another ally, the National Hispanic Christian Leadership Conference, decried the gay provisions, calling their inclusion a “slap in the face to those of us who have fought for years for immigration reform,” Reverend Samuel Rodriguez told POLITICO.

The new push, however, appears to be part of an effort to strengthen support on the left, rather than the right.

“An immigration bill with gay and lesbian families attracts more votes than an immigration bill without them,” Steve Ralls, spokesman for Immigration Equality, said.

That might be true in the House, but not so much in the Senate, where Republican help is needed to overcome a filibuster.

Barney Frank, the straight-talking, openly gay Congressman from Massachusetts, doesn't see it happening.

“You got two very tough issues – the rights of same-sex couples and immigration,” he told the Washington Blade. “You put them in the same bill, and it becomes impossible. We just don't have the votes for it.”