Perthshire Tory veteran Murdo Fraser has sparked anger after he claimed being non-binary was no more valid than “choosing to identify as a cat”.
The Mid Scotland and Fife MSP insisted the SNP should not be devoting resources to support for people who do not regard themselves as either male or female.
It comes days after the Scottish Government unveiled an action plan aimed at improving the lives of Scots who identify as non-binary.
He said: “Choosing to identify as ‘non-binary’ is as valid as choosing to identify as a cat.
“I’m not sure Governments should be spending time on action plans for either.”
Non-binary people are considered to be part of the transgender community, and often use the pronouns they/them, since they do not identify as male or female.
Last December the Scottish Government’s gender reforms aimed at making it easier for transgender Scots to self-identify were met with controversy.
The new laws were initially passed in Holyrood after marathon late-night debates, but were later blocked by the UK Government.
Critics of the policy, including Mr Fraser and nearly all Tory MSPs, claimed the rights of women would be put at risk.
Earlier this year unfounded claims that school pupils are identifying as cats and demanding litter trays spread in the north and north-east.
A string of social media posts alleged, without evidence, that children at Banff Academy, in Aberdeenshire, were asking to be treated like felines.
Council chiefs made it clear that these were “false rumours”.
North East Greens MSP Maggie Chapman, a vocal supporter of the reforms, condemned Mr Fraser’s remarks.
She said: “This is an utterly insensitive and inappropriate thing for an elected representative to say.
“It lays bare the Tories’ complete failure to grasp the fact that binary gender identities are restrictive and fail to capture the full, beautiful diversity of humanity.”
Mr Fraser hit back, saying: “Most Scots are appalled that the SNP-Green Government ignores its day job to promote ideology that threatens the rights of women to single-sex spaces.
“Extremist views such as those of Maggie Chapman should have no place in government.”
Perthshire SNP John Nicolson also waded into the row, criticising Tory rival Mr Fraser.
He said: “You can be certain if there’s something foolish needing said on behalf of the Scottish Tories, Murdo Fraser will be at the top of the queue volunteering to say it.”