The British government has taken steps to block legislation in Scotland that makes it easier for people to change their legally-recognized gender.
The Scottish Parliament approved the Gender Recognition Reform Bill last month. It allows people to change their gender designation on official documents by self-declaration, without obtaining a medical diagnosis that is required in the rest of the United Kingdom.
The British government, under instructions from Prime Minister Rishi Sunak, vetoed the legislation on Tuesday.
It said the bill could allow "fraudulent or bad faith applications," and that predators could switch their gender to access spaces intended for women and threaten their safety.
The British government has the legal authority to block a law adopted by the devolved Scottish Parliament when peoples' rights and livelihoods are judged to be at risk. British media say this is the first time the power has been invoked.
Scotland's leader, First Minister Nicola Sturgeon, vowed to take the British government to court. She accused it of launching a direct attack on the institutions of the Scottish Parliament.
Objections are also expected from people who want semi-autonomous Scotland to break away from Britain. The pro-independence campaign has continued even after the idea was rejected in a Scottish referendum in 2014.