Evelyn Santos began her quest for a green card nearly two decades ago, hoping someday she and her family could leave the Philippines and start a better life in the United States.

The opportunity came in 2007, but with a painful caveat: Her two elder sons were now too old to qualify as dependents, so they would have to stay behind.

The mother moved to Northern California with her husband and two younger children, and filed a new round of paperwork hoping to get at least one of her older sons into the country without another decade of waiting.

"I have a joke with my son — am I still alive when you come here?" said Santos, 55, a supermarket clerk who lives in Livermore. "I am always praying somebody can help us in the government so we can bring my kids here."

Immigration attorneys say thousands of immigrants are stuck in a similar situation. In countries such as the Philippines, Mexico and China, relatives of U.S. citizens and residents sometimes wait a decade or two for a family-sponsored green card because of country-based immigration quotas.

Santos is one of several immigrants across the country suing the federal government to try to get their adult children into the country without another lengthy wait.

Under U.S. immigration law, children 21 and older cannot immigrate under their parents' applications for green cards.

Immigration attorneys say a 2002 law aimed at preventing children from "aging out" due to lengthy processing means these grown children should be allowed into the country soon after their parents file new paperwork on their behalf.

But the government argues that many of those who got too old during the wait are now new applicants and must start from the beginning.

"They want them to go from the front of the line, where they almost made it, and go to the back of some other line that may be 10 to 20 years away, said Carl Shusterman, an attorney representing immigrants in one of the lawsuits. "It is like double jeopardy."

Robert Reeves, an immigration attorney who filed a nationwide class-action lawsuit in federal court in Santa Ana, said he believes 20,000 immigrants living in the United States face similar problems bringing their children here.

Roughly a dozen individuals have filed separate lawsuits in California, New York, New Jersey and Ohio, immigration attorneys said. The complaints argue that the 2002 law allows grown children to use the parents' date of application as a starting point.

The government disagrees and says the law only holds for grown children who were sponsored directly for green cards from the very beginning or for those listed on the application of a foreign parent who was sponsored by a legal resident spouse.

The government contends that Congress passed the law to help current U.S. citizens and residents reunite with their families, not to help future immigrants bring their families here.

The plaintiffs argue that the law reads more broadly than that, and should include adult children whose parents had differing forms of sponsorship, including that by siblings.

The country's immigration appeals court recently ruled in favor of the government in a case in which a Chinese man immigrated in 2005 based on an application filed by his sister. The man tried to get a green card for his daughter, who had aged out, and sought to have her application marked with the initial 1992 filing date. But the court ruled the application was new and his daughter would have to wait.

Sharon Rummery, a spokeswoman for U.S. Citizenship and Immigration Services, declined to comment on the dispute.

Immigrant advocates say the government should not require families to wait so long to immigrate together, claiming it discourages legal immigration. Nor should aspiring immigrants be forced to choose between their children and reuniting with their siblings and parents in the United States.

But some argue these are choices immigrants should have to make. Mark Krikorian, executive director of the Washington-based Center for Immigration Studies, said the lengthy wait times are a symptom of much bigger problems in the country's immigration system.

"There is a deeper policy problem here, which is that we overpromised and underdelivered on legal immigration," said Krikorian, who favors stricter limits on family-based immigration.

"What the advocacy groups are trying to do is fix that system in a way that is beneficial to their constituency group, but it's not solving the problem."

The dilemma has prompted many immigrant parents to urge their adult children to remain single while the lawsuits are pending or until they get green cards. That's because permanent residents cannot apply for their married children to get green cards and must wait to become U.S. citizens to be able to do so.

Teresita Costelo, a 61-year-old cashier in Long Beach, waited 14 years to rejoin her mother and siblings here and does not want her two elder daughters in the Philippines to suffer the same fate.

"I told them, 'Don't marry yet, because I am petitioning you!"' Costelo said. "Just stay single."

Norma Uy, who immigrated to Washington state from the Philippines, waited 23 years for a green card but nearly stayed behind because her two adult daughters could not come with her.

Eventually, she and her husband and their then-19-year-old son packed their bags and arrived in 2005 to start their new lives. The 57-year-old Uy, a trained pediatrician in the Philippines who now works as a nurse, said she encouraged one daughter to come here to study and hopes the other might do the same.

Above all, she wants them to get green cards so they will be able to stay together.

"I know my children will have a better future here," Uy said. "We will have a peaceful life here."