Anglican LGBT rights campaigner Jayne Ozanne has likened calling LGBT relationships sinful to "harmful" homophobia.
She made the comments while weighing in on a dispute between gay students and the Oxford Inter-Collegiate Christian Union (OICCU).
The OICCU has been accused of homophobia after it upheld the orthodox Christian view of sexuality.
The dispute was covered by The Oxford Student newspaper, which quoted several former members of the OICCU criticising the union and its affiliated churches because of their stance on homosexuality.
One student criticised partner church St Ebbe's because it "clearly intended to spread the message that engaging in non-heterosexual activity was a sin".
Another said their time with OICCU had "hugely worsened my mental health".
"Only straight cisgender conservative Protestants—who believe in the superiority of straight cisgender men—can be supported and welcomed," they said.
Ozanne, a member of the Church of England General Synod who is campaigning for LGBT equality in the Church, said she was "so glad" The Oxford Student was "calling out the homophobia" experienced by gay students.
Writing on Twitter, she added: "We can't allow this harmful practice of telling LGBT people who are in relationships that they are 'sinful' to continue. It's damaged and is damaging far too many lives - mine too!"
In a statement, OICCU said: "OICCU welcomes all students from all churches or none to come and join in our meetings and activities. We are pleased to partner with 'Love Oxford' which constitutes a wide range of churches who have a high view of Bible teaching and who are supportive of the OICCU. But, we recognise that there are many other churches in Oxford and that students need to make their own choices."
The Christian Institute's Deputy Director for Communications, Ciarán Kelly, said that churches and Christian student groups should be commended for adhering to a traditional Christian perspective on sexuality.
"The Bible is clear that all sexual acts outside of heterosexual marriage are sinful," he said.
"Churches and student groups that uphold these scriptural truths are to be commended."