Careful with the ole' blood, Mike!
Left-handed, female, bass player. I tick all the wrong boxes.
I write with my right hand (not my mum and dad's fault, though - they've always been very supportive, but it was too late when they realised I had been taught the wrong way).
I have had leftism and sexism thrown at me on many occasions. "Shopping for the boyfriend", "You know, guitars are used this way [righty], not that way [lefty upside-down], let me show you" "You take that long cable with two tips and stick one of them here, see, in the bass, and the other here, see, INPUT", and famously, by an ex-bf's bandmate "Women should either sing or stay backstage ready for the afterparty".
I could go on. However, getting mightily p*ssed off is not the answer IMO. Ignoring the "-isms", charging on regardless towards whatever result you want to achieve, whilst showing no intention to be intimidated, and at the same time being extremely polite throughout, always ends up getting them to blush at their idiocy and finally become helpful.