I think even in the cac population actually having low T, as a young man is very rare, what has happened is, people especially in fitness put many ailments down to 'low t' because they think, and they are probably right it may help them get a prescription from a doctor for testosterone which can help them with their training, Ie feel a bit depressed ? or tired ? must be 'low t'. can't get it up with your girlfriend 'low t', in fact it is very possible to get erection with a low testosterone level as there still won't be anything mechanically wrong with your penis , what low testosterone level does to you sexually,is it makes you not desire sex in the slightest and be very submissive.
Now I know a little about this, as I developed quite an embarrssing problem a few years back and had to see a specialist who did some blood tests, for my hormone levels, my T levels were above normal,but what was interesting was,him saying that even if my T levels were below normal,because of another blood result for another hormone that was above normal,giving me testosterone would actually have an reverse effect as my body was saying it wasn't lacking in testosterone because of that blood result as my body basically reacts more strongly to testosterone than other peoples.
The above,is why it's very important,to see a specialist, and not rely on some dodgy male health clinic,who are more about making money.