Around 50 protesters picketed outside Ballynahinch Baptist Church on Saturday as it hosted the Setting Love In Order conference.
The event, organised by the Core Issues Trust, argued for freedom for gay people to approach psychiatrists and counsellors about their homosexuality.
Delegates heard from a number of speakers exploring issues along the theme of 'protecting the freedoms to believe, to exist and to change when homosexual feelings are unwanted'.
One discussion was entitled: Don't want to be gay any more? Sorry we're not allowed to help you! Is that ethical?
Malachai O'Hara from the Rainbow Project, Northern Ireland's largest LGBT (lesbian, gay, bi-sexual and transgender) organisation, was among the protesters.
He said the kind of 'conversion therapy' being discussed "doesn't work".
"We're here for a number of reasons," he said. "The primary reason is that this therapy has been discredited, it doesn't work.
"Secondly we're here to give out a positive message to people that being LGBT is not wrong, it is not bad, and it can't be fixed.
"In fact what needs to be challenged is homophobia and trans-phobia which causes people to feel that there's something wrong with their sexual orientation and gender identity."
Event organiser Dr Mike Davidson said that the conference was merely to have a debate about the issues of homosexuality.
"We're not busy with a gay cure, we're not busy with conversion therapy," he said.
"Conversion therapy conveys the impression of a light switch – one, two, three and you're done, off you go and live your life. Nothing could be further from the truth."
One speaker, Andrea Williams of the Christian Legal Centre, said it was part of the Christian message to "turn away from sin".
"We're here because we want the freedom for people to be able to access therapeutic support for when they want to reduce same-sex attraction," she said.
"The gospel reality is, of course, that Jesus loves all mankind, he loves every human being and he has a great message of hope for every one of us. But also it's about us recognising what his path and pattern for wholeness is, and that is turning away from those things that are not of him.
"People can choose to change and are free to choose to change, we're not seeking to impose anything, and this is about being free to choose to change if you want."
John O'Doherty, director of the Rainbow Project said this kind of treatment harmed communities.
"This is not a widely held Christian view, this is held by extremist Christians, who are causing huge harm to our community. And we're here today in strength, in numbers, in opposition to this type of therapy in Northern Ireland," he said.
"It's clear from the number of people from Ballynahinch here today, as well as the people from across Northern Ireland who are opposed to this type of therapy, that it shouldn't be happening."
"We're here to give out a positive message to people that being LGBT is not wrong, it is not bad, and it can't be fixed. In fact, what needs to be challenged is homophobia and trans-phobia which causes people to feel that there's something wrong with their sexual orientation and gender identity."
Malachai O'Hara from the Rainbow Project