Peter Tatchell, a human rights campaigner has said it is “highly questionable” to claim a “theological basis against trans people”.
A Catholic commentator it was her "religious belief that a person cannot change sex" after she was reported to police for calling a transgender woman a man on twitter.
Political commentator Caroline Farrow was contacted by Surrey Police after "misgendering" the daughter of Mermaids charity CEO, Susie Green.
Mr Tatchell told talkRADIO’s Matthew Wright: “When you go back to scriptures very hard to find any evidence that being trans is a sin for the Christian faith or people of any other faith.
T”here are no clear or even ambiguous rulings in the great holy books about trans issue .
“Claiming a theological basis against trans people is very flimsy and highly questionable.”
'Wrong and disrespectful'
Mr Tatchell said that "misgendering" should not be a crime but that it was “wrong and disrespectful”.
“Insults, and I suppose this is an insult, should be challenged but I don't think it should be a crime,” he said.
“There are some people who inadvertently use the wrong word and if the intention was not malicious we should talk to them and educate them, not cast them into darkness.”
Ms Farrow said she would "happily do jail time" for her right to say that "a person cannot change sex".
A Surrey Police spokesman said: "A thorough investigation is being carried out to establish whether any criminal offences have taken place."