I didn't think it was gender/sex related either...but the heredity idea is intriguing. Was that an actual, scientific study?
My taste in spicy foods has actually changed, but it was entirely by my own efforts. I used to barely tolerate pepperoni pizza -- sometimes I could eat it, sometimes not -- but at a chili event most of the chili was, of course, spicier so, sick of my pathetic threshold for spice, I basically embraced the burn as a good thing and dealt with it I guess. Was a good day. I've been pushing it further and further since and now things that other people think are spicy I can kind of just shrug at. I truly enjoy spice now.
Though, at my last job, I had a little help with this from an assistant manager, haha.
Unfortunately, when ordering Chinese food, that can lead to disappointment when you want spice and they don't deliver on that.