Transgender 16- and 17-year-olds in Scotland are set to be able to apply to change the sex on their birth certificate for the first time as MSPs debated long into the night the Scottish government’s controversial gender recognition reforms. The marathon session took place amid chaotic scenes at Holyrood, including disruption from the public galley, uncertainty over whether certain amendments opened the bill to legal challenge, and attempts to delay proceedings into the new year. Despite concerns among SNP backbenchers, some Labour members and the Tories, the SNP-Green majority in Holyrood means the bill is highly likely to pass its final stage during a crunch vote on Wednesday afternoon. The bill will remove the need for a psychiatric diagnosis of gender dysphoria, and reduces the time someone must have been permanently living in their gender before they can apply – from two years to three months, or six months for people aged 16 and 17, with a three-month reflection period during which an individual can change their mind. One protester in the public gallery shouted “shame on all of you, there’s no democracy in here” after an amendment tabled by Scottish Tories’ community safety spokesperson, Russell Findlay, seeking to prevent convicted sex offenders being allowed to change their gender was voted down. The debate was suspended for half an hour while the public gallery was cleared, with social media reports that women were “threatened with arrest” if they did not move. Findlay’s amendment was one of a number attempting to address concerns about abusive males taking advantage of the new system. The Scottish government is expected to support another version proposed by Gillian Martin, a Scottish National party MSP who has previously expressed doubts about gender recognition changes, and supported by Jamie Greene, the co-chair of Holyrood’s LGBTI+ group, that would mean anyone convicted of a sexual offence who wants to apply for a certificate will need to be fully risk-assessed. Greene told MSPs that theirs was “not the only unlikely pairing with a shared ambition to strengthen safeguards”. He was referring to Michelle Thomson, one of the SNP backbenchers who rebelled at the first vote, working with Findlay on another amendment to prevent anyone accused of a sexual offence changing legal sex until the end of their legal proceedings. Thomson, who has spoken powerfully about her rape at the age of 14 and its impact on her life, told the chamber that the voices of traumatised women had been ignored in the consultation process, asking: “Who in the past six years has spoken for them?” Shona Robison, the Scottish government’s equalities minister who is leading on the bill, reiterated to MSPs that the threat to women and girls is from predatory men, adding that bad faith exploitation of self-declaration has not been reported in other countries where the streamlined system is in place. The Scottish Green MSP Maggie Chapman warned MSPs that “dog whistles that equate trans people with sex offenders” were “most disturbing”. Efforts by some MSPs to maintain the minimum age for application at 18 were voted down, despite Ash Regan – the former SNP minister who resigned in protest before the first stage of the bill and spoke wearing a scarf in the suffrage colours adopted by opponents of the bill – urging colleagues to “exercise extreme caution”. The session began with concerted attempts from the Scottish Tories to delay the debate into January by drawing out the time taken to discuss procedural motions. Some supporters of the bill were also critical of the amount of time allotted to discuss more than 150 amendments before Holyrood’s Christmas recess begins on Thursday afternoon. There was also anger that three MSPs had been contacted late on Monday by Robison warning that their amendments, if successful, risked putting the bill at “serious risk” of being outside Holyrood’s competence. The UK government has already suggested that it could challenge the bill if it passes, or refuse to recognise Scottish GRCs.