One cheek swab. That is now all it takes to determine whether a player can compete on the WTA Tour. The Women's Tennis Association has announced that, starting this year, every professional player must be tested for the presence of the SRY gene — a segment of the Y chromosome that triggers the development of male biological characteristics. Only a negative result grants unconditional entry to the Tour.

A positive result triggers a further round of medical assessment before any decision is made. The shift is significant. Until now, the WTA's framework — last revised in 2024 — permitted transgender women to compete provided they had maintained testosterone levels below 2.5 nmol/L for at least two continuous years.

That threshold-based approach has been abandoned entirely. The new policy, which the WTA board approved following consultation with players and a review of standards across women's sport, is founded explicitly on biological sex. Players who refuse testing will be required to sign a document acknowledging they could face disciplinary action. The WTA is not moving alone.

World Athletics introduced an equivalent one-time SRY gene test for ranking competitions in September 2025, and World Boxing approved the same method in May 2025. The convergence of three major international bodies around a single biological marker in the space of roughly a year marks a decisive tilt in how elite women's sport is drawing its boundaries. The WTA acknowledged that "this is a sensitive and complex issue" and pledged to treat every player with dignity throughout the process. There are no known transgender women currently playing on the Tour — meaning the policy's immediate practical impact may be limited, but its symbolic and legal implications are already being felt far beyond the baseline.