Why hasn't a filly won the Triple Crown?

Over the past century and a half, only 11 fillies have won a Triple Crown race, and none has won more than one leg during her campaign.

But why is that? Let's take a look at Triple Crown history and analyze the modern state of Thoroughbred racing to find some answers.

History hasn’t been on her side

The 3-year-old filly Ruthless, sired by the famed Eclipse, claimed the inaugural Belmont Stakes by a head in 1867. The Preakness and Kentucky Derby hadn’t yet begun, so her opportunity to compete for the Triple Crown didn’t exist.

Once the Preakness began in 1875, and the Kentucky Derby in 1878, it took three decades for another filly to win one of those races. In 1903, Flocarline — the offspring of Belmont winner St. Florian — beat out her competition in the Preakness.

The thought of racing Flocarline in the Derby or Belmont meant nothing at the time, as the notion of the “Triple Crown” didn’t become common until Charles Hatton used the phrase to write about Gallant Fox’s triumph in 1930.

Whimsical (1906), Rhine Maiden (1915), and Nellie Morse (1924) were the next fillies to notch Preakness victories. In 1915, Regret became the first filly to win the Kentucky Derby, but did not face Rhine Maiden in the Preakness. That was the only season a filly finished first in more than one Triple Crown race.

Only three fillies, from 23 tries in the Belmont, have taken first. Tanya did it 1905, then Rags to Riches ended a 102-year drought for the fillies with a win in 2007.

The Todd Pletcher-trained chestnut won the Kentucky Oaks that year and only joined the Belmont field after Jim Tafel withdrew Derby winner Street Sense from the $1 million race. Rather than compete for the $250,000 Mother Goose, Rags to Riches entered the Belmont and edged past two-time Horse of the Year winner Curlin for the win.

Out of 40 tries for the fillies in the Kentucky Derby, three have won (Regret, Genuine Risk in 1980, and Winning Colors in 1988), two have finished second, and five have come in third.

Genuine Risk finished second in the Preakness and Belmont. Winning Colors is the only other filly to run in all three Triple Crown races. She placed third in the Preakness and sixth in the Belmont.

In 2008, filly Eight Belles nearly beat Derby and Preakness winner Big Brown in the Run for the Roses but tragically suffered compound fractures on both front ankles and was euthanized after her second-place finish.

The fillies' best shot: Rachel Alexandra

It’s been more than a decade since a filly won a Triple Crown race. The Steve Asmussen-trained Rachel Alexandra was the last, when she beat out longshot Derby winner Mine That Bird in the 2009 Preakness. Could she have defeated her counterpart in the Derby, too? Possibly, but the filly entered the Kentucky Oaks that year.

Then trained by Hal Wiggins and owned by Dolphus Morrison, Rachel Alexandra sailed past her female competition in the Oaks and won by 20 1/4 lengths (the largest margin in Oaks history). Following her Oaks victory, Stonestreet Stables bought the filly and put her in the care of Asmussen to prep for her Preakness conquest. She also got the help of jockey Calvin Borel, who guided Mine That Bird to his Derby win but hopped on Rachel Alexandra for the next leg of the Triple Crown.

While many hoped to see the filly contend for the Belmont next, Stonestreet felt it was in her best interest to rest and geared her toward the Mother Goose on June 27. Rachel Alexandra finished first in record time (1:46:33) and by another massive margin (19 1/4 lengths). Summer Bird, at 12-1, took the Belmont.

Racing's culture hinders fillies' chances

Rachel Alexandra could have conceivably won the Triple Crown in 2009, but fillies have disappeared from the American classic races since.

Part of that has to do with the Kentucky Derby point system, which was introduced in 2013 to determine the Derby field. Under that system, fillies would need to run against colts in Derby prep races, which connections have been unwilling to do.

Another factor is money. Considering the purse for the Oaks is now $1.25 million, owners are more inclined to run fillies against an all-female field on Oaks Friday, as opposed to taking on greater risk (and a larger field) in the Derby. In 2018, Rayya became the only filly to accumulate enough qualifying points for a guaranteed post in the Derby and still focused on the Oaks, instead.

The focus on the American classics for males is also aligned with lucrative stud careers.

When Rags to Riches' co-owner, Michael Tabor, was asked about her Belmont victory, he responded, “If it were a colt, it puts a whole different perspective on it. As it’s a filly, we are just here to enjoy and win.”

Unfortunately, with the way American racing has changed, it makes fillies’ pursuit of a Triple Crown all the more difficult. There's no question fillies and mares can compete with males, and they often do in top-level races around the world, just not in the U.S.

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