"genetics" encomposses everything about a person physical makeup. Lines, muscle bellies, bone structure, metabolism, skin tone and response to drugs.
I laugh at idiots who say "it's not his genetics, it's his response to steroids". That's genetics...it's ALL genetics, the entire sport.
the drugs and workout regimens are the same for everyone. it's YOUR GENETICS that make the difference.
Dorian wasn't dry as fuck, and Ronnie was freakishly huge and muscular, because they specifically trained for their respective looks, it's their genetic makeup. they did the same drugs. and they both trained hard.
It's not like Ronnie could say "I want to be dry and grainy like Dorian this year, I'll do what he does and i'll look like that"...he could never get that hard, and Dorian could never hope to have the amount of round muscle that Ronnie had hanging from his frame, it wasn't in his genetic cards.