Despite growing acceptance culturally, research shows almost half - 49 per cent - of young people who come out experience heartbreaking parental rejection.
James Wright was 19 years old when he decided to tell his mum and dad he was gay.
Now 46, the memory of that experience remains clear.
"I would say for all gay people, coming out becomes an indelible memory, whether it's a good or bad experience," he told AAP.
"I came out to mum and dad separately, within a few weeks of each other, and it really shocked me the difference in their response."
Mr Wright's father, a devout Catholic with Italian heritage, was completely accepting.
"He said loving his son was the priority over adhering to what the Catholic Church told him," Mr Wright said.
"It brought us so much closer together ... I felt relieved and that he made it so easy was so beautiful."
His mother, who Mr Wright had expected to be more accepting, did not respond the same way.
"She was horrified," he said.
"We've not had a great relationship since then."
Almost 45 per cent of LGBTQI youth experience high or very high levels of psychological distress and almost half (48 per cent) have seriously considered suicide - more than three times the rate of their heterosexual peers.
The impact of rejection could be particularly devastating for young people beginning to understand and explore their identities, Online Psychologists Australia clinical psychologist Michelle Olaithe said.
"We are seeing increasing numbers of youth questioning their sexuality or gender, reaching out to us out of fear of a lack of acceptance from the adults in their life, or are already facing discrimination and prejudice," she said.
"The impacts of this experience can continue to be damaging for the rest of their lives if they do not get support."
Three in four LGBTQI people have experienced a mental disorder at some point in their lives.
This is not due to a predisposition to poor mental health within the community but rather stigma, discrimination and a lack of acceptance, particularly from those closest to them.
Many people did not realise just how much their first reaction impacted someone who has come out to them, Online Psychologists Australia chief executive Sarah Richardson said.
"The truth is, when someone comes out to you, they're opening up in an incredibly vulnerable way - they're not just telling you something personal, they're asking for acceptance and for safety," she said.
"The best response is to lead with love: say 'thank you for trusting me', tell them you support them.
"You don't need to have all the answers. Just being warm, open and non-judgmental can mean everything in that moment."
The psychologists' platform has released a free guide for parents, teachers, carers and friends as part of Pride Month, celebrated each June.
The guide includes tips on what to say and what not to say, how to be a "safe person" and how to support someone after they come out.
"This guide is for people who care but maybe aren't sure how to respond when someone comes out," Ms Richardson said.
"It's here to take the fear and awkwardness out of that moment and replace it with empathy and confidence."
Mr Wright said he had one piece of advice for the parents of LGBTQI children.
"My advice to parents would be to be brave," he said.
"If you have your suspicions, choose a safe time to raise it, because the child or young adult is probably aching for you to give them permission to talk about it.
"It's your responsibility as a parent to have these conversations and gently give them that opportunity."
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