ST. LOUIS, Missouri (AP) --- A federal appeals court threw out the 10-year prison sentence of a woman who rented her 9-year-old son to a female pedophile more than 200 times, saying the punishment was too lenient.

The 30 year old mother often held the boy down in their home while 52 year old Julie Champion performed various sex acts on him, according to court documents. Champion typically paid the mother $20.

The Associated Press is not naming the woman, to protect her son's identity.

"The factors of this case are no less than horrifying," Judge William Jay Riley wrote in the unanimous opinion released Monday by a three-judge panel.

Champion pleaded guilty and was sentenced to 25 years in prison.

The woman, convicted in 2006 of aggravated sexual abuse and conspiring with Champion to help her molest her son, was sentenced to 17-1/2 years in prison --- the minimum provided under sentencing guidelines.

She appealed, and a panel of judges sent the case back to U.S. District Judge Charles A. Shaw, saying he might have given her a lighter sentence if he had known he was not bound by the guidelines.

Shaw then sentenced the woman to 10 years, saying mental problems and drug addiction had influenced her behavior. The judge also noted that she had taken parenting classes and had vocational training while in prison.

The judge said he did not believe the woman posed a danger to the public and was unlikely to repeat the actions, according to court documents.

The appeals judges disagreed. They found the woman's efforts to rehabilitate herself neither "lessen the horrendous treatment" of her son, nor indicate that she would not again offer her son to an abuser for money.

Kevin Schriener, the woman's attorney, said Tuesday he would ask for a rehearing of the appeal.