A pro-LGBT priest has said that members of the gay Catholic community have been made to feel like "lepers" by the church.
Fr James Martin urged Catholics to examine their own attitudes towards LGBT Catholics and to welcome them into their parish.
Speaking at the World Meeting of Families (WMOF) in Dublin, Fr Martin, who is outspoken in his support for the LGBT community, said the church has caused "deep hurt" against fellow Catholics.
The WMOF was criticised for inviting him to speak after his objectors accused him of promoting views that same-sex marriage is acceptable in the Catholic Church.
An online petition started by the Tradition, Family and Property (TFP) organisation attracted over 10,250 signatures.
There was huge demand for him to be withdrawn from the list of speakers, however up to 1,000 people attended his speech on Thursday in Dublin.
People were refused entry to the hall where he was giving his speech as all seats were taken. However, Archbishop of Dublin Diarmuid Martin stepped in and allowed them to watch it from the back of the room.
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Fr Martin, who is the editor of Jesuit Magazine in America, addressed the crowd about welcoming and respecting LBGT people into parishes.
The American Jesuit and LGBT campaigner, who belongs to the same order as the Pope, said that the more recent challenges facing Catholics is how to welcome LGBT parishioners and their families.
"LGBT Catholics have felt excluded from the church for so long that any experience of welcoming can be life-changing," he said.
"Over the last few years, I have heard really sad stories from LGBT Catholics who have been made to feel unwelcome in their parishes.
"They've have often been treated like lepers in our church. Never underestimate the pain that LGBT people have experienced not only at the hands of our church but from society at large.
"Parishes need to be aware of the consequences of stigmatising LGBT people.
"Many if not all LGBT have been deeply wounded by our church. They may have been mocked, insulted, excluded, condemned or singled out for critique either privately or from the pulpit.
"They never heard the terms gay or lesbian expressed in positive way."
Earlier this year, references and images to the LGBT community were removed from WMOF material.
A number of LGBT say they were denied a stand at the WMOF event taking place at the Royal Dublin Society (RDS).
Fr Martin said that he made a number of observations about how LGBT people are treated and advised Catholics as to how they can be more welcoming.
He said this included six "fundamental insights".
"Parishes need to remember that LGBT people and their families are baptised Catholics, they are as much as part of the church as Pope Francis, your local bishop, your pastor or me," he continued.
"It's not a question of making them Catholic, they already are.
"Just to remain in the church, LGBT Catholics have endured years of persecution and rejection. Our welcome should reflect that reality."
He also said the LGBT people don't choose their orientation.
"Sadly many people still believe that people chose their sexual orientations despite the testimony of almost every psychologist, biologist, and more importantly the lived experiences of LGBT people.
"You don't choose your orientation or gender identity any more than you choose to be left handed.
"It's not a choice and it's not an addiction thus it is not a sin to be LGBT, far less it is not something to blame on someone like parents."
He also urged Catholics to "examine your own attitudes" towards the LGBT community and their families.
He continued: "Do you hold the parents responsible for a gay teen's orientation. Do you think a person is transgender only because it is fashionable.
"Are you discriminating against them in your heart. We tend to focus on whether they are full conforming to the church's teaching on morality. Are you doing the same thing with straight parishioners.
"Be consistent about whose lives get scrutinised. Be honest about your attitudes, but also get facts not myths about sexual orientation and gender identity from scientific and social scientific sources not from rumours and homophobic online websites."
Fr Martin received a standing ovation at the end of his 45-minute speech.
Meanwhile, a number of LGBT campaigners sang outside the front gates of the RDS in protest of the exclusion of gay people and their families from the WMOF.
The Rainbow Choir, made up of LGBT singers, wore T-shirts emblazoned with "hear our voices".
One of the organisers of the choir and former TV3 political correspondent Ursula Halligan said that the Catholic church needs to take more action.
She said: "Fr James Martin is just talking about welcoming and that's great but we need actions, so if the church is truly welcoming they will get rid of this language that calls us objectively disordered and intrinsically evil, and they will say we love you LGBT families and we have no problem with having pictures of LGBT families - but they do.
"So until they change those things everything else is fig leaf, it's window dressing, it's not real but it is a start in the right direction.
"It's not near far enough, the church has to go much further.
"The language they use is damaging and the church in this country controls 90% of schools so I'm doing this for younger people coming out. I don't want them to have to wait until there are 50 years of age before they come out.
"Love is the most important thing in life, why would you try and stunt that in any human being.
"The Catholic teaching is wrong and they have to change that."