The parents of a 3-year-old New Jersey girl say she’s being denied a kidney transplant because of her mental disabilities, but experts caution the situation may be much more complex.

Chrissy Rivera claims a doctor at The Children’s Hospital of Philadelphia said her daughter wouldn’t be eligible for a transplant because of her quality of life and her mental condition.

The hospital says it doesn’t disqualify transplant candidates on the basis of intellectual abilities and has operated on many children with a wide range of disabilities.

Another mother with disabled children started an online petition asking the hospital to give the girl a transplant. By Tuesday the petition had attracted 22,000 signatures.

(Copyright 2012 by The Associated Press. All Rights Reserved.)