Scotland’s Court of Session has ruled that for the purposes of Scotland’s application of U.K.-wide antidiscrimination law, “sex” should be understood to mean transgender identity when individuals are in possession of a “Gender Recognition Certificate” (GRC), an official document saying they’ve changed their legal “gender.”

The decision comes as a blow to For Women Scotland — a group defending sex-based rights against transgender ideology — who were challenging a Scottish law requiring 50 percent representation of women on public boards while defining “woman” as including “a person who has the protected characteristic of gender reassignment.” The group’s lawyer, Aidan O’Neill, argued that the law was conflating two separate categories under the Equality Act (2010), sex and gender, to the detriment of females.

However, Lady Dorian at the Court of Sessions wrote in her judgment published on Wednesday that “it is clear that the intention [of the Equality Act] was that on receipt of a Gender Recognition Certificate, a person’s sex was to be that of their acquired gender, man or woman.”

While this marks a defeat for the sex-based-rights movement in Scotland, the decision could prove helpful elsewhere. Again, the Equality Act is U.K.-wide legislation. In January, the U.K. government issued a veto of Scotland’s gender reform bill using Section 35 of the Scotland Act, a never-before-used legal power allowing Downing Street to block legislation from the Scottish parliament when it is likely to have an adverse effect on U.K.-wide law. The Scottish government is challenging the legality of this intervention.

Writing for UnHerd, Michael Foran explains how Lady Dorian’s recent ruling in the For Women Scotland case may interact with the Scottish government’s challenge of the U.K. government’s use of Section 35:

Because rights under the Equality Act now depend on possession of a GRC, this strengthens the position of the UK Government in the ongoing judicial review of the use of Section 35 of the Scotland Act to veto the Scottish Gender Recognition Reform Bill.

This case clarifies that a GRC is unequivocally not a mere administrative document. Possession of a certificate has wide ranging consequences under the Act. It is therefore increasingly likely that a court will conclude that a Scottish bill seeking to dramatically modify who can obtain one of these certificates does modify the operation of the Equality Act and therefore may engage Section 35.