But Gadson's children - who are ages 6 to 17 - will be long grown by the time he is eligible for parole.
Campbell, who said Gadson's criminal history was marked by "a pattern of violence" and 11 arrests, gave him a sentence that exceeded state guidelines.
The judge also ruled that Gadson is a "sexually violent predator" under the state's Megan's Law, which will require him to register as a sex offender for the rest of his life once he is released from prison.
Assistant District Attorney Kelly Harrell, who had asked for a sentence of 37 to 75 years, said Gadson has never shown remorse for what he did to the 15- year-old girl and her boyfriend.
"This rape - in particular - was brutal," she said. "The crimes that happened in 1998 have changed the lives [of the victims] forever."
The victims - who are now married to each other with children - testified at Gadson's February trial that they were ambushed by two gunmen and forced into Reyburn Park in North Philadelphia just after midnight Feb. 1, 1998.
It was there that the gunmen took turns sexually assaulting the girl and holding her boyfriend at gunpoint, according to the couple, whom the Daily News is not identifying.
Although neither victim could identify the gunmen because they said they were told not to look at them, DNA that Gadson was required to submit to police after being arrested for a robbery eventually linked him to the 1998 assault.
Gadson was arrested in January 2010.
His defense attorney, James Ephraim Lee, told Campbell that his client respects the verdict of the jury that convicted him but still maintains his innocence.
During the trial, Lee argued that Gadson and the girl had engaged in consensual sex and that she told police she had been raped because she needed an excuse for getting home late and missing her grandmother's curfew.
Lee told the jury that the boyfriend was not even in the park at the time of the encounter but that he went along with her lie.
Lee said reasonable doubt abounded in the case, including that only Gadson's DNA was recovered from the victim, though she and her husband testified that there were two rapists.
The second rapist has never been identified, Harrell said.
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