I'm worried that I will never get biceps like this guy http://i31.tinypic.com/aui3ia.jpg

(If that top link doesn't work try http://www.google.com/search?tbm=isch&q=chubby+bodybuilders#i=0)

I read that you can only get so big without using steroids... I'm only 17 and I don't ever want to take steriods... I use that guy as motivation as what I want to look like... So without using steroids do you stop growing muscles once you've hit your genetic size?