Did you know your stepfather is a sexist piece of crap that seems to think that he has a right to dictate how someone that's not even legally related to him should dictate their life? Seriously, I'd imagine that the grades would go down even more so due to the depression that would be caused by such a movement. I wish you the best of luck. By now I've pretty much figured that family is a want not a need. Furthermore it seems really stupid on his part that he would go to the length to discipline you for not doing better, but is he offering to sit down and help you get your grades up? That always gets me, my dad used to try that **** with me all the time, take something away for not being better but never offered to fix it, just made various threats. What a load.