Hmm? I'm afraid I don't quite understand...
Do you not want to teach him simply because he's a guy???
If I saw an ad siting, "Learn to Change Your Own Motor Oil" and the teacher wouldn't accept me as a student simply because I'm a woman, I would be highly offended. :? I think it's the same principal with knitting. Why should he be denied as a knitting student simply because he's a guy? :(
Or do you not want to teach him because you thought his response was pushy?
If he used inappropriate language or griped about your fee, then that's his problem. He should find a teacher whose fees he likes or a teacher who will accept his language.
So if it's simply because he's a guy, I think that would be discrimination, so you might want to consider another explanation for him. If it's because he doesn't like your fee, then just tell him that your fee is non-negotiable. If you think he'll just be a general pain, then you could always jack up your fee to $50 a minute and send him screaming for his mommy
**Hehehehehe** Just kidding ...
Sorry I couldn't be of more help :(