I don't think that your explanation leads to the conclusion that these things are not socially transmitted.
Mountain biking as a sport would not be possible for the average person without the community. Sure, someone could be, and had to be, "the first" MTBer, make knobbly tires, build a suspension, go without a trail, etc, but that sort of spontaneous "new sport discovery" process is not going to happen at anything like the rate that people are attracted (via social transmission!) to the existing sport with everything in place.
The question seems to be whether being transgender, or being a mountain biker, is something that can exist purely in the mind, in the absence of the ability to realise it.
In some ways it feels like an unanswerable question because normal gender roles are socially transmitted anyway, so we can't even say whether "being a man" exists in isolation.
Mountain biking as a sport would not be possible for the average person without the community. Sure, someone could be, and had to be, "the first" MTBer, make knobbly tires, build a suspension, go without a trail, etc, but that sort of spontaneous "new sport discovery" process is not going to happen at anything like the rate that people are attracted (via social transmission!) to the existing sport with everything in place.
The question seems to be whether being transgender, or being a mountain biker, is something that can exist purely in the mind, in the absence of the ability to realise it.
In some ways it feels like an unanswerable question because normal gender roles are socially transmitted anyway, so we can't even say whether "being a man" exists in isolation.