Oscar Passoni-Torres, like many toddlers, is making the transition from crawling to walking. But this 14-month-old also has to wrangle with the additional obstacle of wearing a new prosthetic leg before he is able to take his first few unsteady steps.

Oscar was born with proximal femoral focal deficiency (or PFFD) and fibular hemimelia.

"That basically means he has a short femur bone. He is also missing his fibula," Kari Passoni, Oscar's mother, told CBS News affiliate KOTV in Tulsa, Okla.

As a result, one of Oscar's legs is significantly shorter than the other. Last month he was fitted for his first prosthesis, custom-made to fit over his leg.

Twin Girls from Gaza Get Prosthetic Legs

Kevin Carroll, a board-certified prosthetist with Hanger Clinic, in Orlando, Fla., is working with Oscar and his family and said the toddler is enjoying using his new leg.

"Often times the child will reject it and will try to throw it away," said Carroll. "When you take it off of [Oscar], he tries to pull it back."

Going forward, Carroll said the Passoni-Torres family will have to decide between using surgery to lengthen Oscar's leg over many years or continue to use the prosthesis, which would have to be changed as Oscar continues to grow.

"Sometimes it takes a number of years to determine what approach to take," said Carroll. "He is a little guy after all. He may very well be able to partake in the decision."

In the immediate future Carroll said he expects that Oscar's parents will soon be chasing down the 14-month old as he switches from crawling to walking. It's a transition that will likely happen quickly, since an anonymous donor gave the Passoni-Torres family $500 so that Oscar could practice walking with a gait trainer walker, basically a toddler-size walker that can help Oscar get used to his new leg.

Carroll said that as Oscar grows up, there is no reason he won't be able to participate in any physical activities or sports other kids are participating in.

"If this little guy wants to climb Mount Everest he will do it," said Carroll. "Not a thing in the world will ever stop this kid."

Dancing with Prosthetics

Oscar Passoni-Torres is learning to walk with the help of a prosthetic leg. (KOTV)