I was just wondering. I know a jockey must be of a small build, and as far as I know, male. But, can or has a woman ever been a jockey? Also, related to this, do they have his and her facilities at race tracks? - Jinx
Women started breaking into the profession in the late 60s with Diane Crump. Julie Krone was probably the most successful, though Robyn Smith made the most money by virtue of marrying Fred Astaire.
There’s still a lot of sexism, so it’s hard to break in, but there are no rules prohibiting it; the women compete directly with the men (Krone won the Belmont Stakes). However, being a jockey required a great deal of strength, and many woman just aren’t strong enough.
Wow! You mean they get hit on 2 million times? Boy, I should have gone to the races! Talk about looking for love in all the wrong places! 
Read “Seabiscuit”, which goes into some depth about what it takes to be a jockey. It’s not just riding a horse.
While there are women who can and do succeed at it, it’s not just a matter of of weight. It also requires a fair amount of strength and endurance that is disproportionate to the weight. That is why there won’t be as many females as males in the elite ranks. That does not mean that a woman cannont do it or be successful at it. It just means that, on average, it is a bigger physiological challenge.