The International Chess Federation (FIDE) said it has banned transgender women from competing in its official women’s events while it conducts a “thorough analysis” of developments, a process that could take up to two years.

The new regulations, approved by FIDE’s council this month, will come into effect on Aug. 21 and require transgender players to provide “sufficient proof of a gender change that complies with their national laws and regulations”.

“In the event that the gender was changed from a male to a female, the player has no right to participate in official FIDE events for women until further FIDE’s decision is made,” the federation said.

“FIDE recognizes that this is an evolving issue for chess and that besides technical regulations on transgender regulations further policy may need to be evolved in the future in line with research evidence,” the federation said.

In an emailed statement to Reuters on Thursday, a FIDE spokesperson said the decision was made to better define the processes involved when a player changes gender.

“The transgender legislation is rapidly developing in many countries and many sport bodies are adopting their own policies. FIDE will be monitoring these developments and see how we can apply them to the world of chess,” the statement said.

“Two years is a scope of sight that seemed reasonable for the thorough analyses of such developments. It is to set a certain deadline for a new reiteration of these policies, without rushing it.”

Transgender players can still compete in the “open” categories of tournaments, it added.

Most chess competitions are open to all players, with the exception of a few tournaments such as the Women’s World Championship.

Governing bodies for sports including cyclingathletics and swimming have tightened their participation rules for transgender women in elite female competitions.