Nowadays, though, it’s not true that it’s a medical necessity.
You should say: It isn’t known to be a medical necessity. There are no “truths” in medicine, since doctors understand nothing. There is only what we currently think, and what we used to think. And one day, what we currently think will become what we used to think.
??”?
? J.K. Rowling, Harry Potter and the Order of the Phoenix