There is a popular misconception about that. When you blow into a horn, the moisture in your breath condenses inside. That’s what is coming out of the valve. Even though it’s called a “spit valve,” there’s no measurable spit.
Quoted for imperishable, ringing, rock-ribbed truth. (Jazz musician of some 25 years standing writing.)
The jazz community is remarkably uninterested in much of the rest of the art world’s - or the world’s - values. The ethic of jazz has changed but little in half a century. It is a lot like the skilled craft ethic: both are founded on rigor, individuality, scarcity of work, and individual competitiveness. These just happen to be circumstances that favor male psyches over female.
Supporting my theory, I think, is the fact that most every jazz combo with more than one female is all-female. They just have a better chance at a. staying together and b. getting recognized that way - same as it was 70-80 years ago.
I don’t see any of this changing, BTW. Beyond urban activism or a sort of fuzzy multiculturalism, most jazz musicians (as I said) are uninterested.