A Philadelphia-area family's fight over the rules that govern lung transplants is getting national attention.

Ten-year-old Sarah Murnaghan, of Newtown Square, is dying of cystic fibrosis at the Children's Hospital of Philadelphia.

She needs a lung transplant to survive, but Organ Procurement and Transplantation Network policies say children under age 12 should receive lungs from another child, not an adult. That means it will take longer for lungs to be available to Sarah, who has been on the transplant list for 18 months.

The case has garnered attention in the Philadelphia region and across the country, and spurred discussion about the lung-transplant regulations.

Her family has started a petition on Change.org, asking supporters to urge the Department of Health and Human Services to change the regulations.

"This policy needs to change," the petition says. "The OPTN/UNOS Lung Review Board, a national group of transplant physicians and surgeons, can make an exceptional ruling for Sarah. And they can recommend new policies to OPTN."

As of this morning, more than 72,000 people had signed the petition. The OPTN said in a statement this week it can't change its rules based on one patient.

National news outlets from CNN to Fox News have picked up on the story, and some doctors not involved in Sarah's case say the policy should change.

Dr. Devang Doshi, a pediatric lung specialist at Beaumont Children's Hospital in Michigan, told ABC News that such "hurdles and obstacles" lead him to "get frustrated with the system."

He said: "It's a very disheartening thing to hear and read about because you've got a child in desperate need of a transplant to survive ... and people less qualified in terms of severity are able to get that organ instead of this child because of what's in place."

Art Caplan, a bioethicist at New York University's Langone Medical Center, told the television station that children should be given priority over adults, because kids can have more healthy years with the new lungs.

Caplan elaborated to NBC News that children should get priority in part because many adult transplant patients need new lungs because of their own actions, like smoking, while children are "non-culpable."

"I think we should go back and revisit the system and I think we should give more weight to kids," Caplan told NBC.

Sarah's family has said she has only a few weeks to live and needs a ventilator to breathe.