WASHINGTON (AP) _ The heated debate over whether America should cut the rising numbers of legal immigrants entering the country has put NASA astrophysicist C.T. Vanajakski on edge, upsetting her sleep and her appetite.

Passage of two immigration bills making their way through Congress would put an end to a dream she has nurtured for 10 years _ welcoming her beloved older brother, T.C. Vasudevan, to her home in Sunnyvale, Calif.

Vasudevan, 65, now living in Madras, India, first applied for permission to immigrate in July 1986. He is one of about 2.7 million siblings of U.S. citizens or spouses and minor children of legal permanent residents who are on waiting lists, hoping to enter the United States.

The wait can range from 14 years to as long as 43 years, depending on what country they're living in.

Republicans in the House and Senate say that's one reason why sweeping changes are needed in the legal immigration system. They also say that in these lean economic times, the number of foreigners coming into the United States to live should be reduced sharply, perhaps by as much as 19 percent.

"It is time to slow down, to reassess, to make certain we are assimilating well the extraordinary level of immigration the country has been experiencing in recent years," Sen. Alan Simpson, R-Wyo., said as he introduced an immigration bill in the Senate in November.

The Senate Judiciary Committee is expected to begin work on that bill soon. A similar bill sponsored by Rep. Lamar Smith, R-Texas, would reduce the annual total of new immigrants by nearly 19 percent, from the 804,416 who entered the United States in 1994 to 655,000 by 2001.

In 1988, 643,000 non-citizens were admitted to the country for permanent residence, the most since 1924. That number rose to 1.8 million in 1991, mostly because of the Immigration Reform and Control Act, which legalized 2.7 million illegal aliens who were already in this country.

Smith's bill is awaiting a vote on the House floor, perhaps as early as mid-March. During House Judiciary Committee bill-drafting sessions last fall, Republicans used their majority power to defeat most Democratic attempts to soften the effects of the legislation. Democrats argued there was no need to restrict legal immigration.

Both Smith and Simpson, on a separate track, have proposed measures that would crack down on illegal immigration. This would be accomplished by speeding up deportation of aliens who commit crimes, stiffening penalties for people who smuggle aliens across the border, increasing the number of Border Patrol officers and asking employers to check the Social Security numbers of new hires.

But their ideas on restricting legal immigration have drawn the most controversy.

Among other things, both bills would end a program that allows U.S. residents to sponsor foreign-born brothers and sisters for entry into the country. Most adult children of U.S. residents would become ineligible for family sponsored immigration visas, and the number of family sponsored parents coming to the United States would drop.

News of the bills shocked Vanajakshi, 47, who said she has remained single so she can devote her life to caring for her brother, his wife and their two pre-teen children. It was Vasudevan who got her interested in science as a child, paid for her education and offered to arrange a traditional Indian marriage for her.

"I'm really caught in the middle and I'm extremely upset," said Vanajakshi, who works for the National Aeronautics and Space Administration's Ames Research Center in Moffet Field, Calif. "For days after I first heard about it I couldn't eat or sleep. I'm just really devastated."

In acts of family devotion unusual even in India, Vasudevan, an expert in tax law, international finance and auditing, financed educations and arranged marriages for most of his five brothers and sisters. He even delayed his own marriage until he could find a good match for a sister burdened by a astrological chart considered unlucky for mothers-in-law, Vanajakshi said.

"I don't know how to say this without sounding melodramatic. But really, my whole life centers around him. If I can't be with him, it just knocks the bottom out of my world," Vanajakshi said. "There is no meaning if I can't spend my life with him."

Many Republicans say it's time to look beyond emotions and take a hard look at the way legal immigration works. President Clinton also has said he thinks legal immigration needs to be reduced.

"Our current immigration laws are broken and must be fixed," Smith said. "When immigrant husbands or wives and their young children are forced to wait 10 years to be united, when one-quarter of all federal prisonsers are foreign-born, when one-quarter of legal immigrants are on welfare, it's not a problem _ it's a crisis."

Huge backlogs and the frustration of dealing with the system encourages illegal immigration, Smith said. The United States has become a welfare magnet for foreigners, he said, and the welfare system has become the retirement system of choice for older people around the world.

Current law also allows foreign workers to displace U.S. born workers from American jobs, he said.

Republicans are not unanimous on the issue, however.

House Majority Leader Dick Armey, R-Texas, has said he doesn't want to see legal immigration reduced, and on Jan. 26, Sen. Spencer Abraham, R-Mich., introduced a bill that concentrates on getting tougher with illegal _ as contrasted to legal _ immigrants.

Abraham, the grandson of Lebanese immigrants, said he believes that the Simpson bill goes too far.

"Let's crack down in illegal immigration. But let's keep the Statue of Liberty a shining beacon of freedom and opportunity for those who want to come to America and play by the rules," he said.