The long list given earlier on does indeed have its doubt-raising names, but there are some other considerations here which might lend some balanced thinking to a potentially inflammatory topic such as this.
1. Is male or female homosexuality a self-sufficient descrption or is it more a matter of degree?
2. Where does celibacy fit into this, i.e. is there a danger that some celibates might erroneously be dubbed "gay"?
3. Might not bisexuality muddy the waters of such arguments as have been put forward here?
Furthermore, there has actually been quite a lot of speculative - and, one has to say, often unedifying - "reaearch" that has been forced into an alleged "musicological" mould on this subject in recent years; what useful conclusions, if any, may be drawn from it, however, is quite another matter. If, for example, one listens to a singer's or an instrumentalist's performance - or to the music of a composer - without prior knowledge of the sexual orientations of the performer or composer, how is it possible to draw scientific (let alone correct!) conclusions as to their sexual orientation/s from their respective performance or creative manners? That's if one even assumed that it mattered in musical terms and that one therefore wanted to do so, of course. The neuroscientists of the future might possibly make real discoveries in this field, but until and unless that happens, such speculation will inevitably remain just that - speculation...
Best,
Alistair