Ah, but I do think it’s possible. At 4, he’s barely begun to grasp the sex/gender differences and classify himself. You’ve had years of conditioning.
But we’re talking about ideas. The issue is not so much conditioning as indoctrination. I suspect that you’ve found a mentor who has turned you on intellectually, and friends and lovers who have given you something you needed emotionally that you weren’t getting before, but part of the price of admission was that you wholeheartedly espouse certain core ideas and values.
You write about issues of sexuality and gender as if now, in 2011, we’ve finally figured it out once and for all. Don’t you think a little circumspection is in order? A scholar must believe in her work to be effective, but a stroll through the graveyard of exploded theories ought to make her realize that her sense of certainty is no guarantee of truth. Physicists and biologists are still making discoveries that surprise them—do you really think sociology is infallible?
My point is that a little intellectual humility now might spare you some pain should your son ever decide that he does not regard pansexual polyamorous androgyny as an ideal worth striving for, and that he would rather just be a man.