Due to a recent Supreme Court decision, immigrant children who turn 21 while their parents are waiting in the lengthy process to obtain visas will be forced to go to the back of the line and start over.

In a split 5-4 decision, the justices sided with the Obama administration which maintained that only in limited circumstances does federal immigration law allow for children to retain their place in line after they become adults or "age out" of the system, reports Politico.

The case involved two groups of plaintiffs, including Rosalina Cuellar de Osorio, a Salvadoran mother who was in line for a visa along with her 13-year-old son. However, after years of waiting, her son turned 21 and government officials said he no longer qualified as an eligible child. As a result, he was pushed to the back of the line and forced to wait of several more years for a visa.

A 9th U.S. Circuit Court of Appeals ruled in favor of the family, but the Supreme Court reversed that decision.

Writing on behalf of the majority, Justice Elena Kagan said the court was required to defer to the interpretation offered by the government. According to the government, the law directs immigration officials to automatically convert a 21-year-old child's petition into a category for adults. That means only immigrants can keep their spot in line only if they would already qualify under the valid new adult category.

Immigration advocates argue that the law was passed to promote family unity and that forcing an aged-out child to go back to the end of the line would increase his or her wait time by more than nine years.

Justice Sonia Sotomayor wrote in a dissenting opinion that the law should be read to allow all aged-out children to keep their place in line. She added that the case should have been decided with a "commonsense approach," reports Reuters.