Former prime minister Tony Abbott says some same-sex marriage advocates have attempted to set a disappointing tone to the debate.
Former prime minister Tony Abbott has warned against "moral bullying" ahead of a national postal vote on same-sex marriage.
Mr Abbott also criticised advocates who are against the public vote and want a full fledged parliamentary solution for implying Australians can't be trusted to "have a sensible debate and make a considered decision".
The postal vote, due to be finalised by November pending the outcome of a High Court challenge, was announced last week by the federal government.
The coalition had previously pushed a plebiscite, which was Mr Abbott's own initiative and was taken to the last election by his successor Malcolm Turnbull.
"Last week, one very senior Labor senator attacked the prime minister for allegedly exposing her children to 'hatred' because of their family circumstances," Mr Abbott wrote in The Australian on Tuesday.
"It is not homophobic to maintain that, ideally, children should have both a mother and a father.
"Yet I fear much moral bullying in the weeks to come - invariably from those demanding change."
Mr Abbott also said it was "a pity the advocates of change haven't finalised what they think are fair protections for freedom of religion and freedom of speech in an era of same-sex marriage because it's hard to be sure about something without knowing exactly what it may entail".
Mr Abbott says voting no is not a criticism of one's gay friends and family members or an "assertion that there's only one right way to live your life or to express your love".
Rather, he says, it will be "an affirmation that the things that matter should not lightly be changed and that marriage is different from other relationships".