The cashier hands me my change , gives me a wide grin and lays on that old familiar sign-off. "Thank you, sir," she says brightly.
There was a time when such mistaken identity would make me apoplectic.
"What's your problem?" I would ask. "Don't you have eyes? Are you so messed up by sexual stereotypes that you can't tell the difference between a man and a woman, even a woman who wears a D cup? Gimme a break."
Nowadays I'm finding that I just smile back. Except for those times when I'm hassled on my way into the women's bathroom, I don't even correct the offender.
Does this mean I've lost my feminist edge? I know I still believe that women have the right to female-only spaces and I'm still super-proud of my dykedom and my lesbian motherhood. But at the same time, I'm warming to the idea of my gender fluidity.
It's not an entirely new thing. I've rejected the butch label for years, even though people make all kinds of yawn-inducing assumptions about where I fit on the butch-femme spectrum.
The truth is, the more experience I have, the more I see myself as ever-morphing. I change depending on who I'm with. In the company of an über-butch I become a little more femmy, but give me a high femme and I can do butch with the best of them.
You don't have to be queer to get my point. If you've been in more than one relationship, you've got a sense of how different people bring out different aspects in you.
But it doesn't matter how common fluidity is in the experience of individuals. Our world is not very tolerant of any sexual presentation other than super-male or -female. Ask even the most progressive parent whether he or she would send a young son to daycare in a skirt and the answer, trust me, will be no. Too dangerous.
The pressure starts early. Just after our daughter was born I went to the nursing station to ask for a baby blanket. "Boy or a girl?" the nurse dutifully asked.
I stared her down. "It's a cold baby," I said, irritated that the pressure was starting so soon. The child was 19 minutes old, for chrissake.
And don't get me started on how difficult it is to find baby clothes that aren't colour-coded for gender, or how the cosmetics industry is still making a killing by reinforcing the gender-centred pressure on women to wear the equivalent of facial masks.
Yet while I've been exploring the upside of ambiguity, some in the LGBTTIQ community are passionately seeking more clear-cut gender definitions for themselves. While I'm feeling liberated by my softening edges, some trans people feel they're liberated by their transition to a specific gender.
It's left me wondering what it feels like for a person contemplating a sex change to know with such confidence who they really are. Given the ridiculous male-female dichotomy we're forced to live with, do any of us know what our real gender potential is ?
Like many feminists, I'm grappling with the polarity issue. The data on wife assault is very clear: the more extreme the sex roles in a relationship, the more likely it is that male violence will occur. When we confine men to the demands of "masculinity" and pressure women to comply with outdated definitions of "femininity," we're inviting trouble. Breaking out of this binary system has to be a key component of any program to end violence against women.
But this data relates to heterosexual relationships between biologically born men and women, and besides, it tells us nothing about trans experience. It just seems wrong to suggest that people transitioning are promoting these extremes and setting us back. Many trans people embrace the idea of fluidity, still identify as queer, and some choose a sex change precisely because their pre-transition gender ambiguity makes them more vulnerable in a world that tolerates nothing but extremes.
Speaking of getting hurt, I have to wonder (though I know I'll catch flak here) whether trans people who are taking hormones and making surgical changes to their bodies are causing pain to themselves?
When I raise this with folks who have transitioned, they say absolutely not. It feels, they say, like something's finally being made right. Which is why anyone passionate about sexual liberation has to respect these decisions and support full funding for medical treatments.
Some trans people allow that in a world that embraces gender uncertainty, trans women might not choose some of the more cosmetic changes removing the Adam's apple, for example, or more extreme procedures like peeling back the facial skin so bone can be shaved to smooth the face.
But when I ask them whether they can imagine a future in which they would not feel compelled to transition, every one says something like, "Go ahead, Susan, create a fluid culture. I'd still be happier being the person I've become."
I believe them. And in the spirit of Pride I celebrate their courage, honour sexual pluralism and invite everyone on the planet to challenge the tyranny of assumptions that prevent us from being who we really are.