Have you ever SEEN a body-building or weightlifting magazine or book? EVERY ONE OF THEM touts the possibility of enhancing strength, muscularity, and flexibility through intelligent training. It happens all the time to people who are not professional athletes.
But you, Harry, have concluded that it is not possible for Barry B to have built himself up through rigorous gym training, just like thousands of other guys have done.
And for the record, anabolic steroids do not produce muscle mass. You still have to work your ass off in the gym to get those results. In fact, those who have done so merely say that the steroids allow them to work harder in the gym than they could have without the steroids.