Though it may be decades, Joe Harris Sullivan is waiting to die in prison for a crime he committed at age 13, one of thousands of children who have been sentenced to life terms without parole in the United States.

The Supreme Court on Monday announced that it will decide whether sentencing juveniles to spend the rest of their lives in prison without hope of ever being released can be considered a cruel and unusual punishment.

The justices are taking up two cases from Florida challenging life sentences for teenagers. In the first case, a judge determined that 17-year-old Terrance Graham took part in an armed home-invasion robbery while he was on probation for a violent crime.

Sullivan, now 33 and in prison at the Santa Rosa Correctional Institution in Milton, Fla., was sentenced to life in prison without possibility of parole for the rape of Lena Bruner in 1989. Bruner never saw her attacker, but she testified at trial that Sullivan's voice sounded like that of her attacker. Two boys also testified against Sullivan, a police officer said she saw Sullivan run from Bruner's house, and his handprint was found on a plaque on Bruner's bed.

Sullivan had been found guilty of 17 criminal offenses, including several serious felonies, in the two previous years, officials said. The state destroyed the case's DNA evidence in 1993.

Bryan A. Stevenson, Sullivan's lawyer, said Sullivan was one of only two 13-year-old children sentenced to life without parole for a non-homicide crime in the United States and only one of eight with that sentence for any crime in prison.

Times have changed people's minds about sentencing juveniles, Stevenson said.

The Supreme Court in 2005 outlawed the death penalty for juvenile criminals in the case Roper v. Simmons, declaring there was a national consensus that such executions were unconstitutionally cruel and ending a practice that had brought international condemnation.

A 2008 report from Human Rights Watch said that there are 2,484 youth offenders serving life without parole in the United States, with Florida, California, Louisiana, Michigan and Pennsylvania having the highest number. The United States is the only country in the world that still sentences juveniles to life in prison without possibility of parole, Stevenson and other advocates said.

"I don't think there has been a lot of awareness about the sentences some of these kids have received, and so I do think it presents a serious question," Stevenson said.

Bill McCollum, Florida's attorney general, filed court papers in Sullivan's and Graham's cases.

The Supreme Court "has recognized that a state is permitted to make 'a societal decision that when a person who has previously committed a felony commits yet another felony, he should be subjected to the admittedly serious penalty of incarceration for life, subject only to the state's judgment as to whether to grant him parole,"' McCollum said.

A Florida appeals court upheld the sentences of Sullivan and Graham.

This is not the first time this court has been confronted with the question of juveniles spending their lives in prison. Last year, the justices declined to consider an appeal of a 30-year prison sentence for a teen who was 12 when he killed his grandparents in their South Carolina home.

The cases will not be heard until the fall term. The Supreme Court is expected to have a new justice by October following the retirement of David Souter.

The cases are Sullivan v. Florida, 08-7621, and Graham v. Florida, 08-7412.