I'd be shocked if that's not illegal in most instances already.

Many states allow minors to consent to their own medical treatment under a variety of circumstances. Some are in the case that the minor is homeless, emancipated, or in an emergency situation.

Idaho actually allows minors to consent to any procedure as long as they can comprehend the procedure and it's risks. See Idaho statutes 39-4503.

"Any person...who comprehends the need for, the nature of and the significant risks ordinarily inherent in any contemplated hospital, medical, dental, surgical or other health care, treatment or procedure is competent to consent thereto on his or her own behalf. "