Christians have strongly criticised Lib Dem leader Jo Swinson's promise ahead of next week's election to "completely reform" the Gender Recognition Act.
On Twitter, Swinson said that if the Lib Dems come to power, the Act will be changed to remove the requirement for people to provide medical reports in order to legally change their gender.
Posting with the hashtag #BrighterFuture, she said the party would recognise non-binary gender identities and scrap the £140 fee to apply for a Gender Recognition Certificate.
She then said that the Lib Dems would introduce gender-neutral school uniform policies and "break down outdated gender stereostypes of certain subjects".
Swinson ended her thread with a promise to introduce a gender-neutral 'X' option to British passports, and "extend equality law to cover gender identity and expression, ensuring a #BrighterFuture for everyone".
Her tweets drew criticism from a number of Christians, several of whom said they would not be voting for the Lib Dems because of its position on gender.
Evangelist and commentator David Robertson replied to her tweets, saying: "And that's why your campaign is in free fall. The Lib Dem's have turned from a moderate party into an extremist one. This is an insane anti-women policy that does so much harm at many levels. Ill thought out virtue signalling. You won't get my vote."
Cathy Madavan, author of Digging for Diamonds, wrote, "You have just lost my vote at the last minute. Yes to compassion but no to policies that put women at risk," with Christian author and speaker Sheridan Voysey responding to her tweet, "You took the words right out of my mouth, Cathy."
Peter Lynas, head of the Evangelical Alliance Northern Ireland said: "This is just bizarre - anti-women, anti-science, anti-common sense, unworkable and not even written in understandable sentences!"
The Titular Archbishop of Selsey, the Most Rev Jerome Lloyd, made similar comments, writing that the proposals would put children at risk.
"Your manifesto is anti-women, anti-science, anti-faith, unsafe for children and ultimately dehumanising, socially divisive and ironically, misogynistic," he said.