The U.S. Secretary of Health and Human Services said she can't intervene in transplant decisions and move a dying Delaware County girl to the front of the line.

Kathleen Sebelius said those decisions should be made by medical experts, but she has called for a review of transplant policies so more organs become available to children.

Sebelius said she "can't imagine anything more difficult" than the situation facing Sarah Murnaghan's family.

The 10-year-old Newtown Square girl has been hospitalized at Children's Hospital of Philadelphia for three months with end-stage cystic fibrosis. Her family wants an exception made for Sarah to get an adult lung because so few pediatric lungs are available.

Sebelius, speaking Tuesday before a congressional committee, said there are three other children at the same hospital who are just as sick.

Sarah's relatives said they want the policy changed for all children awaiting a lung transplant, not just Sarah.

Her aunt, Sharon Ruddock, said older children should be eligible for adult lungs. She said that would add just 20 children to the 1,600 people on the adult waiting list.