The UK government has said it could try and block the Scottish Parliament’s decision to allow transgender people to self identify.
MSPs passed the Gender Recognition Reform (Scotland) Bill passed by 86 votes to 39 on Thursday.
It will remove the need for a medical diagnosis of gender dysphoria to obtain a gender recognition certificate (GRC).
It would also lower the minimum age for applicants to 16 and drop the time required for an applicant to live in their acquired gender from two years to three months – six for those aged 16 and 17 – though with a three-month reflection period.
But Alister Jack, the Scottish secretary in Westminster, said the British government could try to block the new law in the courts.
“We share the concerns that many people have regarding certain aspects of this Bill. and in particular the safety issues for women and children,” he said.
“We will look closely at that, and also the ramifications for the 2010 Equality Act and other UK wide legislation, in the coming weeks - up to and including a Section 35 order stopping the Bill going for Royal Assent if necessary.”
MSPs had undertaken an intense debate on the issue this week, spending more than 24 hours in the consideration of amendments and final vote.
The passage was marred by protests, as opponents of the legislation interrupted proceedings as Social Justice Secretary Shona Robison brought the debate to a close, and other shouted “shame on you” from the public gallery after the final vote.
Opponents of the legislation have questioned its potential impact on women and girls, particularly in relation to single sex spaces, while the Scottish Government has said little will change.
The new law has caused rebellions across the chamber, with SNP MSPs announcing before the vote they would defy the whip, while Scottish Tory Jamie Greene dissented from his party’s view, although the Tories were given a free vote on the issue.
Speaking in the final debate on the Bill on Thursday, Robison said: “Every party in this chamber except one made a clear commitment to the reforms set out in this Bill at the last Scottish election, and at the one before that it was all parties.
“Members from all parties in this chamber voted to support the general principles of the Bill at stage one.
“At this final stage, I urge all members to vote in favour of these important reforms and for the Bill, I move the motion in my name.
“Trans rights are not in competition with women’s rights, and as so often before, we can improve things for everyone when those discriminated against act as allies, not opponents.”
But Scottish Conservative MSP Rachael Hamilton said the Bill “has shown this Parliament at its worst”.
She added: “In the rush to make the process a little easier for trans people, the Government is making it easier for criminal men to attack women. That’s the problem here.”
The Equality Act features exemptions for single-sex spaces where trans people can be excluded in certain circumstances – exemptions Robison has said will not change.
Labour’s Pam Duncan-Glancy said the legislation provides MSPs with “one of those rare moments… where we all have a real opportunity to improve lives and directly tackle inequality”.
She said the Bill will help “society to accept them (trans people) and to support them to be their best selves, without barriers or additional costs or medicalisation”.
Duncan-Glancy insisted: “I believe strongly the reform we will vote for today has been a long time coming, and that is why changing the current onerous, lengthy and invasive process of legal gender recognition has always been so important to me.”
MSPs spent 24 hours this week debating it after two marathon sessions considering amendments on Tuesday and Wednesday – with the latter finishing at 1.15am on Thursday.
The Tories have been accused of an attempt to filibuster the legislation, proposing numerous points of order and forcing almost all amendments to votes that were sometimes not required.