What do gay men want? How not to find out

It seems that everyone has an opinion on what gay men want in a partner, and that opinion is usually backed up by that unimpeachable source known as "because I say so." Some people, however, have made an actual effort to find out, although that effort still typically falls short. For example, I recall reading one study of personal ads in The Washington Blade, drawing conclusions as to whether more gay men prefer smooth or hairy men. One problem with that approach is self-selection bias. I am sure that the same study done with Recon.com profiles would have reached the opposite result. Then there is the problem of counting gay men who do not run personal ads at all.