ARTICLE AD BOX
Nicola Sturgeon has said the UK government would be using trans people as a "political weapon" if it decides to block Scottish gender reforms.
The first minister said any veto of the legislation would be an "outrage".
The prime minister must decide this week whether to use powers which would stop the legislation becoming law.
Ms Sturgeon also criticised Labour leader Sir Keir Starmer for saying that 16-year olds were too young to decide about changing their gender.
Holyrood MSPs backed a move towards a self-identification system last month.
It would mean that people in Scotland would no longer require a medical diagnosis to change gender. The timescale involved would also be reduced.
The UK government is considering using its own powers to block the Scottish legislation.
Under Section 35 of the Scotland Act, UK ministers can stop a bill getting royal assent - a power which has never previously been used.
'Political decision'
Ms Sturgeon said: "There are no grounds to challenge this legislation, it is in the competence of the Scottish Parliament.
"It doesn't affect the operation of the equality act and it was passed by an overwhelming majority of the Scottish Parliament after very lengthy and intense scrutiny by MSPs of all parties.
She added: "So if there is a decision to challenge, then in my view then it will quite simply be a political decision and it will be using trans people, already one of the most vulnerable stigmatised groups in our society, as a political weapon.
"I think that will be unconscionable, indefensible and really quite disgraceful."
UK ministers have concerns the Scottish system could come into conflict with UK-wide equalities law.
Rishi Sunak has said he was concerned about the potential impact on other areas of the UK.
The prime minister said the government was taking advice on the implications of the reforms "as is completely standard practice".