Trans women will no longer be able to play in female rugby tournaments under plans being drawn up by its international governing body.
World Rugby allowed trans women to play women's rugby if their testosterone levels were reduced for at least a year but this is to change,The Telegraph reports, following a review of the organisation's policies in light of the latest peer-reviewed evidence.
The decision reflects a concern for the safety of biologically female players, as well as fears of legal action, the paper reports.
World Rugby said that a "clear safety risk" remained in contact rugby even if testosterone is reduced because this "does not lead to a proportionate reduction in mass, muscle mass, strength or power".
The policy change is to be discussed by national governing bodies ahead of a meeting of the World Rugby council in November.
The plans do not affect trans men who will still be allowed to play alongside biological males.
A spokesman for World Rugby said: "World Rugby and its unions are united in their commitment to ensuring a safe and inclusive playing environment at all levels of the game.
"In line with this commitment, and in light of the latest peer-reviewed research, World Rugby has undertaken a wide-ranging review of its rugby-specific transgender guidelines in order to best reflect the modern playing landscape and scientific evidence.
"Throughout the process, World Rugby has sought to balance safety and inclusivity. The latest peer reviewed research confirms that a reduction of testosterone does not lead to a proportionate reduction in mass, muscle mass, strength or power. These important determinants of injury risk and performance remain significantly elevated after testosterone suppression.
"Rugby is an inclusive and welcoming sport and World Rugby is fully committed to continuing to work with relevant groups to explore appropriate participation pathways for transgender athletes and is funding further research into the safe participation of all players in rugby. This is in addition to extensive non-contact participation avenues that are available to everyone at union level."
Dr Nicola Williams, Director of the women's rights advocacy group Fair Play For Women, welcomed the decision, saying that World Rugby was "setting the gold standard for how all sports should approach this; evidence-based policy making that delivers inclusion where possible but always safety first".