Every player on the women's professional tennis tour will have to provide a cheek swab and be screened for a single gene in order to be eligible to compete.
The Women's Tennis Association has adopted a one-time screening for the SRY gene, the marker that ordinarily sits on the Y chromosome and initiates testis development in a fetus. A WTA spokesperson described it, in a statement carried by Al Jazeera, as "a required, one-time screening process for the SRY gene." Because a person's genome does not change, the tour treats it as a once-in-a-lifetime test.
Reports differ on the precise date the rule takes effect, with the tour's own rulebook revision and news accounts of the announcement pointing to different days this month. Player screening is set to begin during 2026.
What the test does and does not establish
A negative result clears a player to compete. A positive result does not automatically end a career: players with certain differences of sex development, including complete androgen insensitivity syndrome, may still be found eligible after further medical assessment.
That exception matters, because it is also the scientific objection. Someone with complete androgen insensitivity has the SRY gene and does not respond to androgens, developing along a female phenotype. The gene is present; the physiology the policy is concerned with is not.
Andrew Sinclair, among the geneticists credited with identifying SRY, has cautioned that the marker cannot carry the weight now placed on it. Sex, in the framing of a review published in the National Library of Medicine's collection, is "much more complex, with chromosomal, gonadal, hormonal and secondary sex characteristics all playing a role." That same review notes that in athletics, restrictions on endogenous testosterone were not accompanied by clear evidence of the performance gap they were meant to address.
Governing bodies dispute that reading. World Athletics, which introduced its own SRY screening for the female category in 2025, has described the test as a reliable proxy for biological sex and argues a clear line is preferable to case-by-case hormonal monitoring.
What it replaces
The WTA's previous approach was hormonal. Players who had gone through male puberty could compete if they held testosterone below a set threshold for a sustained period before and during competition. The new rule abandons measurement of the body in favor of a fact about the genome.
The tour has framed the change as protecting competitive integrity and aligning with recent Olympic guidance. It has also acknowledged, according to reporting by the tennis journalist Ben Rothenberg, who obtained the policy documents, that no transgender women are known to be competing on the professional tour.
The argument among players
Tennis has unusually prominent voices on both sides, and they do not agree.
Martina Navratilova has been among the most outspoken opponents of transgender inclusion in women's sport. Aryna Sabalenka, the world number one, has said she considers it unfair for women to face transgender opponents. Billie Jean King, whose standing in the sport comes substantially from a career spent fighting for women players, regards exclusion of transgender athletes as discrimination. Advocacy groups take the same position.
These are genuine disagreements among people with real claims on the sport, and the tour has moved without resolving them.
Privacy, and a long memory
The sharpest practical objection concerns confidentiality. Rothenberg's reporting on the documents describes players being asked to acknowledge that a failed test "may lead to the reason for my ineligibility becoming public knowledge or being the subject of public speculation."
For a player who learns through a mandatory swab that she has a condition she did not know about, that is an unusual thing to be asked to sign.
The history explains why critics react strongly. The Spanish hurdler María José Martínez Patiño failed a sex chromatin test in 1985, was publicly identified, lost her place and her scholarship, and spent years fighting to be reinstated. The International Olympic Committee abandoned mandatory sex testing in 2000 in part because of cases like hers. Legal scholars at Yale Law School argue the current wave of genetic screening conflicts with the IOC's own non-discrimination commitments and with laws protecting genetic information.
The WTA's position is that a bright line is fairer to the field than the alternative. The objection is that the line is being drawn with an instrument that its own discoverers say was never meant to settle the question.
