That's the truth DX. The first thing that FiL said when I mentioned this to him was "I don't know anything about babies..."
Now, whilst that's obviously not completely true, when it comes to serious illnesses or medical conundrums like this, then you need the real experts and even someone who is highly qualified, but in a slightly different field, might start getting things mucked up. All Drs use caveats if it isn't an area of specific knowledge. (Well, good ones do anyway!)
You wouldn't ask an Airbus pilot about a Boeing. They might know the basics, but unless they know the systems in and out, then things might get confused.