I contend we are all gay to varying degrees.
While I've seen no science that supports the notion that humans, both male and female, can be exclusively gay or straight, I have seen studies done that suggest sexual orientation is not an either/or proposition but rather a matter of percentage. Sexuality should be seen as a continuum.
It's a lot like handedness. People are primarily right or left handed, but that doesn't mean there aren't some things a righty does better with their left hand or a lefty with their right. I'm probably 80% left handed, maybe you're 80% right handed. but no one I've ever met has been exclusively left or right handed. In the same way I don't believe anyone is exclusively gay or straight. They might prefer to live a life that appears exclusively gay or straight, but that's behavior, not orientation.
Many people who self-identify as exclusively gay or straight are horrified by the suggestion that they might harbor even a small percentage of the opposite orientation within them. That's understandable but I believe mistaken.
I see nothing wrong with accepting that we are complex sexual creatures who are by varying degree both gay and straight, realizing that fact only in a particular circumstance or context or perhaps never at all. If societies hadn't demonized homosexuality the way a majority of them have, based on purely emotional and unscientific beliefs, perhaps we'd have an easier time coming to grips with our own sexuality and our lives would be that much richer and rewarding. As it is very few even among the most open-minded of individuals are comfortable considering the possibility that we are only predominantly gay or straight and not exclusively one or the other.