My homophobia is genetic. It's physical because of the involuntary reaction my body has toward homosexual stimuli. Homophobia is like any other inborn defense mechanism. It helps to protect us from bodily harm. Thanks to the way Mother Nature made us.
Homosexuals make most people gag.
As with other defense mechanisms, homophobia is genetically inherited. I know it is inherited because I was not taught this behavior. My revulsion to homosexuality is among my earliest memories. Now that I've come out of the closet, my life is more fulfilling. I have met many other homophobes like me.