Basically, in assessing the capacity of a minor person, we are trying to establish that they can have a full understanding of the information, and that they can process all the different alternatives available to them and make a decision that is reproducible if we have the same conversation with them again. What we're trying to establish is that they have an adult level of maturity and reasoning.
I think the difficulty is that the younger the child is, the more there are issues that may be at play in terms of trying to please others, including their parents and sometimes their religious and spiritual advisers, and they may even have beliefs about what is good for their family or what will be good for their siblings, for example. I think this is the reason that when it comes down to a life-and-death decision it's very often referred to the court, because those sorts of things are not clear. I think health care teams often want to refer to a higher authority for that decision to be made if the child is at risk of losing their life.