Good topic.
Can we look at the differences between the average male jockey, and the average female one ? bearing in mind that there are ALWAYS exceptions to any rule.
For starters, the women tend to be finer-boned and with lesser tendon/ligament strength , and also a different shape.
The body configuration has to have some bearing upon the way it hits the ground after a fall, and bone density must also have a bearing on overall fragility or otherwise.
The ability to 'roll' after a fall was discussed at the track only recently, where the vests came in for some criticism.
They have improved since first introduced, but have been held up by some people as a big cause of neck/head injuries because the wearer is unable to roll up as before, but is hurled directly onto the ground - like a spear dive.
I do seem to recall, that before vests were introduced, one of the more common results of a fall [ among males ] was a broken collarbone, where the girls seemed to hit the ground head-first.
Not sure if that was ever statistically indicated, but it certainly appeared to be the case.