The Utah Supreme Court has upheld prison sentences of three child sexual abusers who filed a class-action lawsuit claiming imprisonment violated their constitutional rights.

The unanimous justices upheld a lower court decision dismissing the lawsuit filed by Craig B. Herman, Thomas J. Opfar and Bobby Lee Boog Jr. The decision was published Friday.The trio, all serving minimum-mandatory sentences at the Utah State Prison, said their rights to equal protection under the law were violated because other child sex offenders have been convicted of similar crimes but given more lenient sentences.

The men, who represented themselves, filed a lawsuit in 3rd District Court on behalf of other inmates in a similar situation.

The men said Utah's child sex abuse statutes require minimum-mandatory sentences, except in cases of incest, where judges are given some sentencing latitude. Those convicted of aggravated child sex crimes face minimum-mandatory sentences ranging from five- to 15-years-to-life.

Yet they claimed some defendants not falling into the so-called "incest exception" have received suspended sentences, sentence reductions or probation.

Third District Judge Scott Daniels rejected their claims, and the trio appealed his decision to the Supreme Court. To prove their case, they submitted newspaper articles and court pleadings.