BILLINGS - This Mother's Day, many people will celebrate all the ways moms have made their lives special. But for a growing number of American children, it will be a day spent longing for a mother who is locked behind bars.

Mothers are the fastest growing prison population nationwide. At the Montana Women's Prison in Billings, no card, bouquet or gift can fill the void for mothers separated from their children. Gina Montgomery: "This will be my second Mother's Day here. It'll be hard because it'll be a reminder I'm not there. And I should be. But because of my own mistakes, I'm not."

Gina Montgomery was 8 months pregnant when she was locked up for stealing more than $20,000 dollars. The birth of her son Jimmy combined the greatest joy she'd ever experienced with the greatest sorrow she'd ever known when she had to leave him at the hospital and return to jail.

Montgomery recalls with tears streaming down her cheeks, "In the last 16 months I've seen him 28 hours. That's not very much time at all. I still remember the pain."

Inmates here at the Montana Women's Prison are mothers to 125 children somewhere on the other side of the barbed wire. In many ways those children pay for their Mothers' sins as studies show they suffer emotionally, struggle with schoolwork and are six times more likely than their peers to follow their mother's footsteps and end up in jail.

Those numbers are hard for Gina Montgomery to swallow. She's determined to somehow be there for her son in a way her mother wasn't there for her. "I want to tell my son I've been to prison, this isn't a place for you. It's nobody else's fault but your own."

While other moms enjoy flowers, cards and cuddling, Mother's Day for Montgomery will be a reminder of all she's missing. Her message to moms on the outside: "don't take your kids for granted. They could all be taken from you in an instant. It's the little mistakes that catch up to you. Your child should be the most important thing to you. It doesn't matter what you give them, it's your time that means the most."

It's that kind of time many of these women only dream of, while they wait out their sentences, worry about their kids and wish they would have made better choices.

Montgomery's son is with his father and spends a lot of time with his grandparents. But currently, many of the babies born to women in custody do not end up with their fathers or relatives at all. Coming up Monday, KULR-8's Kathy Weber shows just how vulnerable newborns become when their mothers are in prison.