mature minor → ώριμος ανήλικος
The mature minor doctrine is an American rule of law accepting that an unemancipated minor patient may possess the maturity to choose or reject a particular health care treatment, sometimes without the knowledge or agreement of parents, and should be permitted to do so. It is now generally considered a form of patients rights; formerly, the mature minor rule was largely seen as protecting health care providers from criminal and civil claims by parents of minors at least 15.
https://en.wikipedia.org/wiki/Mature_minor_doctrine