Here is something from Animal Pak, and I find it quite amusing:
Q: As my biceps get bigger, I've developed stretch marks on them. How do I get rid of them?
A: Your kiddin' me right? You're concerned about stretch marks? Most guys would cut their balls off to have stretch marks on their arms, especially the bicep. The guys I talk to all want to know how they can get bigger arms. If you have stretch marks, it means that your arms have grown. Who gives a flying fuck about stretch marks? Know what? If your worried about growing and getting stretch marks, then I have an idea: Why don't you take up knitting instead? This way you don't have to worry about that kinda shit. The only things you'll have to worry about are patterns and yarn colors.