Let's ask this:

For those of you who self-identify as gay, could it be that you have simply not yet encountered a female to whom you are attracted?

For those of you who self-identify as straight, could it be that you have simply not yet encountered a male to whom you are attracted?

In other words, while you might find sex with somebody of the other/same gender not to your liking based on what you've experienced thus far, is it not within the realm of possibility that you might find it, if not enjoyable, then at least something that you might consider trying, simply if you were to meet the "right" person?