When Rachel Alexandra’s owners decided to run her in the Kentucky Oaks instead of the Kentucky Derby, many racing fans were disappointed.

Over the last two weeks, much has changed: Rachel Alexandra was sold and her new owners ponied up the additional $100,000 necessary for late entry into the Preakness. The Preakness field is limited to 14 starters and to accommodate Rachel Alexandra, at least two stables decided not to run a second horse.

Speculation about her chances has been rampant all week and she’s starting tomorrow as the favorite.

Rachel Alexandra is described as a “superfreak” of a filly. That’s in a good way. She’s won all four of her starts in 2008 by an average of 10 lengths and smoked the field at the Kentucky Oaks, cantering home 20 lengths ahead of the field.

In the 134 years that the Preakness Stakes has been run only 52 other fillies besides Rachel Alexandra have run in this prestigious stakes race. In fact, it’s been 10 years since a filly has run in the Preakness; in 1999 Excellent Meeting started but was pulled up and didn’t finish. Only four fillies have won the Preakness Stakes: Nellie Morse (1924), Rhine Maiden (1915), Whimsical (1906), and Flocarline (1903). Rachel Alexandra is the first filly to run in both the Kentucky Oaks and the Preakness.

In the U.S. mixed gender races are unusual. Three year old colts (and geldings) generally are physically and stronger than fillies of the same age and it takes a special filly to compete. This is not so much the case in other parts of the world: last year Vodka, a 4-year-old filly, became Japan’s Horse of the Year after twice beating males and Zarkava, a 3-year-old filly, became Europe’s Horse of the Year after she became the 17th female to win the Arc de Triomphe.

According to Gary West in the Star Telegram, the reason for segregating colts and fillies may have more to do with economics:

“While some valid reasons may argue against running a filly against colts, this strict segregation by gender is partly, I suspect, the result of brainwashing. Breeders, who exercise far too much control over the sport, generally would prefer to see a colt win the Triple Crown races, and for a good reason: A mare can produce one foal a year; a stallion can sire a hundred.”

Can Rachel Alexandra hold her own against the “boys”? So far this year she’s shown that her peers offer little competition. She deserves the chance to compete in the best of the stakes races. One thing is for certain: with all the publicity surrounding Mine That Bird and Rachel Alexandra, it promises to be one of the most watched races in Preakness history!

To give everyone a preview of this great filly, here are some of her recent races (with Calvin Borel in the irons).