Shawn Callahan has always been supportive of legalising gay marriage. This view was galvanised two years ago when his eldest daughter, Alex, told him she was gay.
"The thing that really struck me and my wife was the realisation that her life would be more difficult than it had to be, that she's going to have a harder road to travel than others," the 50-year-old said.
Mr Callahan fears his 21-year-old daughter will face discrimination over her sexuality in the form of stereotyping and intolerance in the workplace if Australia's political leaders do not do more to support gay people, including backing marriage equality.
He said failing to legalise same-sex marriage reinforced prejudice and a sense that there was "something that's not quite equal with that group".
Mr Callahan, who has close gay friends and family members, said common arguments against same-sex marriage – that it is detrimental to a child's development or "normalises" homosexual behaviour – did not make any sense to him.
"My nephew was brought up by a lesbian couple and he's a lovely fellow who is in a heterosexual relationship. It had no detrimental impact on his life whatsoever," he said.
"These are people who are in long-term, loving relationships, very normal people with normal values that we know from a heterosexual world. The evidence that sits around me is contrary to the arguments that I hear against it."
Mr Callahan, who lives in Pascoe Vale South, said he was surprised by the result of the referendum in Ireland, but hopeful reform could be achieved in Australia.
"Somehow they managed to separate the religious perspective from the human rights perspective," he said. "I'm also surprised there are so many states in America that support marriage equality. If they can support it, where's Australia on this? We seem to have fallen way behind."
Marc de Castella firmly believes children raised by two parents of the same sex are bestowed a "cruel emotional deprivation" and are "psychologically disadvantaged towards heterosexual relationships in adulthood".
The secondary school teacher, who does not have children, said he had met many students over his career who were raised in same-sex households and unhappy about their upbringing.
"They seem to be fairly dissatisfied with the situation and in some cases really determined to distance themselves completely from that lifestyle," the 48-year-old said. "In my experience it engenders a fair degree of bitterness in children."
Mr de Castella, a Catholic who holds a degree in philosophy, said the traditional family structure was indispensable because of the moral, practical and emotional role mothers and fathers play at different stages of a child's development.
"Judeo-Christian marriage, with its commitment to heterosexual monogamy and its inherent focus on the family unit, is the bedrock of Western culture," he said. "In the typical heterosexual marriage, children absorb, assimilate and learn to appreciate the gender-specific qualities of a man and a woman."
Mr de Castella, who lives in Yarra Junction, said Ireland's decision to legalise same-sex marriage had placed enormous pressure on the federal government, and he feared the result of a conscience vote or referendum in Australia. "I certainly hope there is not a referendum because I think it would pass and that will unwind the remaining moral fabric of this country."
He said he believed political correctness was being "thrust upon us" and that people who shared his views would be accused of being fundamentalists or homophobic. "The fact is I would never show the smallest degree of prejudice to someone who is gay or lesbian. I'm simply opposed to the lifestyle."
