Majority of my friends are females, too. I went to vocational school and it turned out to be a female dominated trade (surface treatment) despite of being under the construction category. In contrast, I also have straight male friends, although not as many. But, as far as I know, no friends are gay, bi, etc.
Usually the problem I have with guys is their topics. Cars, computers (and technology in general), army time... Yeah, I'm not interested in the least. 😀 I seriously share more interests with my female friends. xD