Very similar to transfusing kids of Jehova's Witness. If it is life or limb saving, do what you need to do. You don't need a court order if it is an emergency. If the kid is a 17 yr old and is "mature" then this can get a little sticky. Still some states hold to the 18 yr old = adult only hard and true.
Right off the Sullivan's Group Physicians Law Review:
Generally, state and federal courts support parental control over the basic matters affecting their children. However, when parental actions have resulted in inadequate medical care, courts in the United States have stepped in to decide between parent wishes and physician concerns. Under the doctrine of "parens patriae" (the state's paternalistic interest in children) the state will not allow a child's health to be seriously jeopardized because of the parent's limitations or convictions. A parent does not have the authority to forbid saving their child's life. Courts invariably rule in favor of a physician who claims that a parent is denying standard medical care to a child.
Under the doctrine of parens patriae, the state represents the best interests of the child. The state also looks to the child abuse and neglect statutes, which provide for protective custody when the child has not received medically indicated treatment.
Once again, the emergency physician is empowered by understanding the law. If parents withhold consent, and there is a life threat, the emergency physician should take temporary protective custody based on child neglect. It helps to explain to the parents that this is a medical obligation under the law, and you will immediately report to the hospital administrator, hospital attorney and the local child protection agency. The parents will typically stand down and allow you to proceed with your mission. Even in situations where the minor's life may not be threatened but severely impaired, the courts usually will order medical treatment over the parents objections.
