(ABC News) - Mariah Walton suffers from a debilitating condition that could have been fixed with surgery. 

But, her parents chose to pray for healing instead of seeking medical treatment.

She was born tor parents who don't believe in the power of doctors to heal. So Walton never even knew she was born with a birth defect until it had devastated her body, leaving her disabled and very angry.

"I would have terrible headaches to the point where I would be sobbing it hurt so bad," said Walton. 

20-year-old Mariah Walton was born with a hole in her heart. 

"I couldn't catch my breath, and my lungs are on fire. I had this sensation like my feel felt like they were falling asleep, like needles in my feet," described Walton. 

It could have been repaired by surgery, but Walton says her parents did not seek treatment. 

"My mom's reaction was that I needed to be prayed over, have more supplements, something that would cure what I have having, and she wouldn't take me to a doctor," said Walton.

Her parents are practicing fundamentalist Mormons who believe in faith and prayer to treat illness. 

"When I tried to bring it up, they don't talk about it. Sweep it under the rug. It's not even true," said Walton. 

Emily Walton, Mariah's older sister, regrets not trying harder to intervene. 

"I regret not taking her to the emergency room. I feel terrible about that," said Emily Walton. 

Mariah grew up in Idaho -- 1 of 32 states that provide a religious defense against potential crimes specifically against children, including neglect, endangerment, and abuse. 

"My parents deserve to be prosecuted. It's unfair of my parents to just throw me into this situation, and my sister has had to support me," said Mariah. 

Kids who are in need of medical care can still make a report to Child Protective Services to other mandatory reporters in order to force parents to provide them with medical care. 

Marian and her sister were recently part of a panel discussion about the issue at the Idaho state capital. Both hope the exemptions currently in place are lifted. 

"I hope to accomplish getting this law repealed so people like me will not have to suffer anymore," said Mariah. 

Mariah's best hope is for a heart and lung transplant -- a highly complicated and risky surgery. But it's her only chance for a future life. 

In the meantime, she gets emotional and financial support from her siblings.