As far as i can see Mark is not committing any sin by taking roids. Vanity doesnt fly. I go to church every sunday and have read the bible many times and have never had sex, or drank, or taken any drugs(coke,weed,etc). But i have done a couple cycles. I dont consider them a sin. It is not a sin to want to improve yourself. It is a sin to want to make someone feel bad because they dont look as good as you, that is vanity. Taking roids would be a sin if you are doing it for the wrong reasons