There is another dimension to it, apart from the aforementioned tendency for men to engage more in high-risk (money-wise and otherwise) behaviour than woman.
A lot of the original crypto people came from the computer geek community. If you think of the origins of Cryptocurrency, BitCoin and Cryptography, e.t.c, they came from the Maths, Physics and Computer Science people. That's why most of the original miners of Bitcoin were usually from the IT (Information Technology) and Computer Programming/Security fields. The vast majority of these people are men.
The computer gaming community also jumped on it quite quickly - because of the kind of gamification of the mining process - again another community of majority men/boys.
Of course there are some women that got into it early too, but they also tended to be from those communities, in which they'd been the tiny minority.
As Crypto gets more of a smily face (like Steem), hopefully there will be more mass adoption by the general public.
Great points @adetorrent! The 90% number isn't necesarily representative of the current active crypto users - as so many of the early miners and accumulators were men - and so it will take a LOT of women owning crypto to start changing that number.
hahah this actually made me smile! Way more fun than just saying "user friendly"... but YES couldn't agree more that mass adoption to the general public will likely come through chains like steem that can offer more mainstream feeling dapps.