"I want to try and make his life as normal as possible," says Angela Avant.
Avant and Patricia Walton, Marlon's grandmothers, told Marlon's story in their letter to The Early Show's "Week of Wishes."
The letter said: "Dear CBS wish grantors. On June 14, 1999, I welcomed Marlon C. Moore Jr. into my life. To our surprise, it was discovered that he had a small quarter-sized opening at the base of his back. Soon after, we were told that Marlon had spina bifida."
Spina bifida, a neural-tube defect, left Marlon with uncontrollable bladder function and paralysis below his ankles. But a brace on each leg has done nothing to slow Marlon's spirit.
There's also plenty of encouragement from Marlon's family, which has endured an emotional three and a half years.
"Spina bifida children usually don't walk, they are usually confined to a wheelchair. And I was, like, I hope this is not the case with him," says Patrice Walton, Marlon's mother.
"It hurt me a whole lot. I cried — a grown man crying — in the delivery room for days and days," recalls Marlon's father, Marlon Moore Sr. "But I don't even like to talk about it, you know, because I don't want to put it on his mind. Because he's fine, you know. Really."
Because his paralysis was limited, Marlon was able to begin physical therapy at three months and was walking by his third birthday.
"Therapy has really been a tremendous help," says Patrice.
And it has led the way for Marlon to enjoy the simple pleasures of childhood like dancing, running with his friends in the school yard, and playing with big brother, Daniel.
But Marlon's favorite pastime may be his passion for all things Elmo, the brightly colored puppet with a squeaky voice from PBS' Sesame Street.
"Ever since I could remember, our grandson has been a die-hard fan of Elmo," says Patrice.
This leads to the wish of Marlon's grandmothers: "To have him be on national TV with Elmo and also to show other kids that you can ...overcome any disability that you have by just having a fun and happy spirit," says Avant.
There's no disappointing a proud grandma. So, The Early Show co-anchor Hannah Storm went to Sesame Street to arrange a special play date for Marlon.
Elmo was more than happy to oblige, but he wanted Storm to make sure it was OK with his parents to head for CBS' studio to play with Marlon. It's a task that wasn't too hard for Storm.
On Monday, The Early Show was able to make a wish come true as Marlon meets Elmo for the first time.