Utah Code Title 76. Utah Criminal Code § 76-5-305. Defenses

(a) the actor was acting under a reasonable belief that:

(b) the alleged victim is younger than 18 years old or is a dependent adult, as defined in Section 76-5-111, and the actor was acting under a reasonable belief that the custodian, guardian, caretaker, legal guardian, custodial parent, or person acting in loco parentis to the victim would, if present, have consented to the actor's conduct.