It has been 37 years since the U.S. Supreme Court ruled that Renée Richards be allowed by the USTA to play women's tennis. Someone had better tell CrossFit.

Last week, CrossFit, Inc. was sued for discrimination by Chloie Jönsson, a transgender woman who was told that if she wants to compete in the CrossFit Games, she would have to do so as a man. ("Transgender" is an umbrella term, referring to anyone who identifies with a gender that they were not assigned at birth. Most publications now refer to an individual's gender based on that person's own statement of identification. A "transgender woman," for example, refers to any adult who identifies as female but who was assigned the male sex at birth.)

CrossFit, whose representatives declined to comment for this story, is a fitness company whose events and programs enjoy a devoted following. It is not just a workout or a sport; it's a life philosophy, and its founder, Greg Glassman, is a self-described "rabid libertarian." Some critics have compared it to Scientology, with participants encouraged to discount conventional fitness wisdom, and even some enthusiasts have described it as a cult-like. Its trademarked name is fiercely protected by legal counsel Dale Saran, who wrote a brusque response to Jönsson's initial complaint. Its tone is in keeping with CrossFit's image: Complaints are for the weak, and dissent is unwelcome:

Chloie was born, genetically -- as a matter of fact -- with an X and a Y chromosome and all of the anatomy of a male of the human race. Today, notwithstanding any hormone therapy or surgeries, Chloie still has an X and Y chromosome. Thus, you're [sic] statement is categorically, empirically, false.

Saran is perhaps unfamiliar with the case of South African runner Caster Semaya and the existence of intersex individuals. There are people born with XY chromosomes whose assigned sex at birth was female. Chromosomal testing is no longer used by the International Association of Athletics Federations, the organization that tested Semaya in 2009, nor is it used by the Olympics. Instead, when questions do arise about an athlete's gender, hormone testing is considered more authoritative than a DNA test. There are a number of scenarios in which an individual's chromosomes would read "male," but that individual's hormone levels would register within the typical range of a female.

The NCAA, the IOC, the LPGA and the IAAF have all adopted updated guidelines for transgender athletes over the last decade. Last week, at the very first SXsports panel, Athlete Ally founder Hudson Taylor discussed Jönsson's lawsuit, highlighting that the NCAA established new "best practices" guidelines two years ago for transgender athletes, while a new proposal suggests that transgender collegiate athletes should be given a medical year for transitioning, without losing a year of eligibility. As for the Olympics, "femininity testing" ceased after the 1996 Summer Games.

Yet CrossFit still insists that an athlete must compete based on "gender at birth," preventing Jönsson, a 5'4" woman according to her CrossFit Games page, from competing with women. It's hard not to read CrossFit's position as discriminatory, since endocrinologists and athletic bodies agree that there isn't an actual, competitive advantage. The Australian Sports Commission sums up the arguments against allowing transgender women to compete:

Within the debate are several assumptions, that:

• anyone exposed to testosterone at puberty will be a good athlete
• all males make better athletes than all females, and
• males will change gender in order to reap rewards in women's sport which they are unable to obtain by competing in men's sport.

"All of these assumptions are false," the report concludes, in a statement similar to one issued by the NCAA: "The assumption that all male-bodied people are taller, stronger, and more highly skilled in a sport than all female-bodied people is not accurate." Likewise, the Women's Sports Foundation's position paper reads: "... medical experts increasingly agree that the effects of taking female hormones negate any strength and muscular advantage that testosterone may have provided and places a male-to-female transgender athlete who has completed her transition in the same general range of strength and performance exhibited by non-transgender females who are competing."

Unsurprisingly, the competitive-advantage argument has been used only to exclude transgender women from competition. Transgender men have had a wide array of experiences in high school basketball (Tony Bias), college basketball (Kye Allums) and college volleyball (Taylor Edelmann). The regulations adopted by the NCAA and the Olympics reflect a perceived advantage gap, in that transgender men may immediately compete in men's sports, while transgender women must have varying lengths of time on hormone therapy before they may compete with women.

If there's no competitive advantage, then what exactly is CrossFit's objection? There's already a precedent for transgender women competing without completely destroying a sport. Why would CrossFit mandate that an athlete out herself -- or fear being outed, if she already is transitioned?

CrossFit also embraces "paleo living." Its website suggests: "Search 'Google' for Paleolithic nutrition, or diet. The return is extensive, compelling, and fascinating. The Caveman model is perfectly consistent with the CrossFit prescription." It also counts advocates of barefoot running or minimalist footwear (such as Vibram FiveFingers) in its number. CrossFit advocates see their fitness routine, food and footwear as being in accordance with how people lived 10,000 years ago, so perhaps their attachment to the idea of a perceived "natural order" should not come as a surprise.

CrossFit's attorney, Saran, also responds with great offense to a reference by Jönsson's attorney, Waukeen McCoy, in which McCoy compared her treatment to segregation in baseball. Saran responded in his letter: "… your comparison to the plight of African-American baseball players fails both in the physical reality and on its own terms in the particulars." Saran seems oblivious to the long history of genetic advantages being used to generalize black athletes as well. Genetic determinism isn't just a losing argument, it's a terrible PR strategy.

McCoy, on the other hand, has a history of winning rulings for plaintiffs for discrimination on the basis of sexual orientation and gender identity. He was a part of the legal team that successfully argued In re Marriage Cases in front of the California Supreme Court in 2008, and won a record-setting $120 million in punitive damages in a 2000 racial discrimination suit against Wonder Bread. History, science and legal firepower are all on Jönsson's side.