BD hit it dead on... just as he always does. It all comes down to how you generate your traffic.
I don't sell young men/twinks well because my traffic is coming from hairy/mature/leather men sites. And the surfers that are on my sites are most likely not interested in twinks.
Dalimili, may I suggest that you limit your approach to what interests you. If you absolutely love scawny white boys with caved in chests or grotesquely obese black men with dreadlocks, that is what you are going to be the most successful at marketing... at least to start. Once you become the master of your niche, then it's time to expand into other areas.