The Republican-backed measure proposes reserving 55,000 permanent residence visas for foreign graduates of U.S. universities with master's and doctoral degrees in the "STEM" disciplines of science, technology, engineering and math.

Some Democrats argue that the plan unfairly pits lower-skilled immigrants against those with more education in the battle for visas as the new law would eliminate an existing program, often called the green card lottery, that provides visas to 55,000 people from countries with lower rates of immigration.

Many Democrats, including President Barack Obama, oppose the Republican bill as it moves ahead a narrow measure instead of focusing attention on a comprehensive immigration reform.

The bill on Friday passed 245-139 in the Republican-controlled House, largely along party lines. But the legislation has little chance passing in the Democrat-controlled Senate.

Democrats, emboldened by strong support from Hispanics and other minorities in the November 6 election, are pushing for a large immigration overhaul that would put 11.5 million immigrants who are now in the country illegally on a path to citizenship - a major point of contention between the two parties.

Broadly, both parties agree on the benefits of helping science and technology experts stay in the United States. U.S. law already gives foreign students in STEM fields extra time to legally stay in the country after graduation to find work.

Texas Republican Representative Lamar Smith, chairman of the House Judiciary Committee who had introduced the "STEM Jobs Act," said the high-tech visa program would help retain U.S.-trained workers to spur innovation and job creation.

"In a global economy, we cannot afford to educate these foreign graduates in the U.S. and then send them back home to work for our competitors," Smith said.

STEM jobs, including teaching positions, account for roughly 6 percent of the U.S. economy, according to Nicole Smith, a senior economist who studies the issue at the Georgetown University Center on Education and the Workforce.

"We know some of the best schools in the world in those areas are found in the United States... This is a chance for them to cut out the red tape" and help graduates stay, she said.

The number of STEM jobs is expected to grow by 17 percent by 2018, outpacing broader job growth, Smith's research found.

But not quite a quarter of them will require a graduate degree, which Smith said raised a question for narrowly targeting highly-educated workers: Will there be sufficient demand for their skills?

"There is this pre-occupation with people with master's and PhD's in STEM," she said, adding that much high-tech work relies for example on lower-educated technicians.

In debates on the House floor on Friday, Democrats argued that focusing on advanced degrees gave preferential treatment to better-educated workers at the expense of the lower-skilled workers who make up a large portion of U.S. immigrants.

"Talk about picking winners and losers," said Rep. Luis Gutierrez, an Illinois Democrat who chairs the Immigration Task Force of the Congressional Hispanic Caucus.

"There was no special line for PhD's and master's degree holders at Ellis Island. There was no asterisk on the Statue of Liberty that said your IQ must be this high to enter."

(Additional reporting by Richard Cowan; Editing by Xavier Briand and Leslie Gevirtz)

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