It's an interesting point, but with no actual analysis into why girls are less likely to ride than boys, given that all of the key take-aways are made up of non-gendered responses.
I think the biggest issues for cycling in the UK are
- The state of the roads
- The lack of cycle paths (and their condition when they do exist and aren't just cycles painted on the road
- The attitudes of drivers
- Parents not encouraging kids to ride more because of the above issues
Blissfully I learned to cycle in the 90s when road quality was better and the road weren't as clogged. As a result I'm a confident cyclist even now. My nieces and nephews aren't as lucky; the roads the live near are potholed, and traversed by cars which have gotten unbelievably big.