If you have a loved one who is unable to make decisions for his or herself due to being underage or otherwise not having the capacity to do so, then you might want to consider a guardianship. In Iowa, according to the Iowa Governor's Developmental Disabilities Council, having guardianship over someone means you get to make the decisions for that person in regards to important issues, such as medical care.
One point to keep in mind is that a person's right to make decisions for him or herself cannot be stripped away without a very good reason. The court will make you prove why the person is incapable of making his or her own decisions. In general, you must prove the person will harm him or herself in some way if the decision-making rights are not taken away.
Even if you do manage to prove there is a viable reason, you may not be given complete rights to the person's decision making. You may be granted only the right to make medical and financial decisions, for example.
The reason why guardianship rights may be limited is to allow the person to retain his or her basic rights to be able to make decisions about his or her life, which is something all adults have the right to do. In making a decision, the court usually will be very conservative, granting the least constrictive guardianship rights. This information is for education only and is not intended to be used as legal advice.