Christine Smith will never forget the moment she watched her 21-year-old son being led out of a Florida courtroom in handcuffs.

"This is not happening, this is not happening, this is not happening," she recalls thinking at the time. "Take me instead."

She sobbed because there was nothing she could do. Matthew, the second of her three children, was going to prison after pleading guilty to 10 counts of possession of child pornography. A judge in Duval County sentenced him in April 2010 to 18 months in state prison and one year of probation, with the requirement that he register as a sex offender.

She told herself that they were lucky, that he could have received a longer prison sentence. But her worries extended far beyond prison. Under Florida law, he would likely remain on the registry for life, with the opportunity to appeal for good conduct. Where would he live after being released? How would he find a job? What about harassment? Would he ever date again? Who would want to marry a sex offender?

Smith is one of many mothers preoccupied with these questions on a daily basis. These women embody the notion that a mother's love is unconditional as they're often forced to look beyond horrific crimes that have left their children branded for life as sex offenders.

What's a mom to do?

"Mothers want to deal with everything, no matter what happens," Smith said. "It doesn't matter how old they are or if they do something stupid. You're there to pick them up and help them get through."

That devotion comes at a high price, as parents often assume some of the responsibility and burden of the sex offender designation. They mortgage their homes so they can buy a new place for their child beyond residency restrictions. It has ended marriages and friendships and divided families.

Like Smith, many fear that their sons will forever be lumped in the same category as child molesters and rapists, and channel their grief through activism.

Matthew Smith and his mother, Christine.

Dozens of parents of sex offenders declined to discuss their experience for this article, fearing that doing so would bring harm to their families.

"My son and I have just started to experience some level of peace and stability. ... It's not worth digging up the harassment again," one woman said in an e-mail calling off an interview with CNN. "No one understands the threats, harassment, loss of income and dignity. I hope you find someone that can better take the risk. [We] have suffered enough humiliation."