There really isn't a good reason for so few. Shocking, I know. :) We make weight easier (*note: this is not a personal strength) and stamina/strength isn't an issue. As one rider in the above article put it, "The horses are the ones running around." It seems like the overall reasoning is that female jockeys aren't given enough time/rides to reach mastery. The most successful women who are able to compete are largely in the position to do so because their fathers are owners/etc.
For example, the first woman to receive a jockey license was Anna Lee Aldred, back in 1921. While it seems obvious that anyone who has parents in a particular field has an advantage, Anna Lee is another example, as she was the daughter of a trainer.
The highest placing female jockey placed 5th in the 2014 Kentucky Derby: Rosie Napravnik. So, no 1st place winners thus far! Here's an adorable photo of Rosie competing in pony racing. HILARIOUS. I need to go see a pony race! Sidebar: I also learned about an amazing charity~ Old Friends. They started in 2003 when Ferdinand, a Kentucky Derby winning horse, died in a slaughterhouse. Not cool. How unfair to win thousands of dollars off a horse and then throw him/her away like garbage. Donate to this amazing charity!
Finally, without wanting to set back women jockeys, I found out that 4 women have died in the last 14 months riding. No men. Everyone says it's a freak coincidence, however, but who knows?
Want to know more about specific ladies? Check out this Wikipedia page.
