Nicola Sturgeon has said the UK authorities would beryllium utilizing trans radical arsenic a "political weapon" if it decides to artifact Scottish sex reforms.
The archetypal curate said immoderate veto of the authorities would beryllium an "outrage".
The premier curate indispensable determine this week whether to usage powers which would halt the authorities becoming law.
Ms Sturgeon besides criticised Labour person Sir Keir Starmer for saying that 16-year olds were excessively young to determine astir changing their gender.
Holyrood MSPs backed a determination towards a self-identification strategy past month.
It would mean that radical successful Scotland would nary longer necessitate a aesculapian diagnosis to alteration gender. The timescale progressive would besides beryllium reduced.
The UK authorities is considering utilizing its ain powers to artifact the Scottish legislation.
Under Section 35 of the Scotland Act, UK ministers tin halt a measure getting royal assent - a powerfulness which has ne'er antecedently been used.
'Political decision'
Ms Sturgeon said: "There are nary grounds to situation this legislation, it is successful the competence of the Scottish Parliament.
"It doesn't impact the cognition of the equality enactment and it was passed by an overwhelming bulk of the Scottish Parliament aft precise lengthy and aggravated scrutiny by MSPs of each parties.
She added: "So if determination is simply a determination to challenge, past successful my presumption past it volition rather simply beryllium a governmental determination and it volition beryllium utilizing trans people, already 1 of the astir susceptible stigmatised groups successful our society, arsenic a governmental weapon.
"I deliberation that volition beryllium unconscionable, indefensible and truly rather disgraceful."
UK ministers person concerns the Scottish strategy could travel into struggle with UK-wide equalities law.
Rishi Sunak has said helium was acrophobic astir the imaginable interaction connected different areas of the UK.
The premier curate said the authorities was taking proposal connected the implications of the reforms "as is wholly modular practice".