There are three reasons to vote “no”. The first is because as Christians, we are called to be a voice for the voiceless.

Redefining marriage in law redefines families because the right to marry is a compound right which includes the right to form a family.

It is true that same-sex couples are raising children now, but it is not all rainbows.

Same-sex marriage activists are pushing for Australia’s ban on commercial surrogacy to be lifted, and their lobbying has reached the ears of the Australian Human Rights Commission (AHRC). In a 2015 report, the AHRC canvassed the need to legalise commercial surrogacy so two men can enjoy full “marriage equality”.

It is the responsibility of Christians to stand with and for those who do not have the backing of the AHRC, including the vulnerable women who will be enticed to sell their eggs, rent their wombs and then hand over their babies. Christians must also speak up for those children who will be raised without a mother or father as a result of the creation of a public policy which says that’s okay.

Yes, it is true that same-sex couples are raising children now, but it is not all rainbows. Lesbian-raised Millie Fontana is a friend of mine. She is not a Christian but has spoken at ACL events, thanking Christians for being the only ones in this debate to stand up for the rights of people like her.

She says there’s another side to the rainbow. Sadly, her voice is unwelcome in this debate.

The same-sex marriage movement will concede only narrow religious freedom protections …

The second reason to vote “no” is for freedom. The same-sex marriage movement will concede only narrow religious freedom protections for professional clergy only.

And even that is through gritted teeth, as the submissions of the movement’s leaders to the recent Senate Select committee show.

Some, like Shelley Argent of PFLAG (Parents and Friends of Lesbians and Gays), want even the protections for professional clergy abolished.

Chris Pycroft, Co-Convenor of the NSW Gay and Lesbian Rights Lobby, told the Senate that if religious freedom exemptions are to be granted, they should be reviewed in two years’ time.

It is naïve to think that a movement which likens opposition to same-sex marriage to racism and hate speech will allow any exceptions to stand in the medium to long term.

In Australia, Archbishop Julian Porteous was taken to the Tasmanian anti-discrimination tribunal for distributing Christian teaching on marriage.

The most prominent leader of Australia’s same-sex marriage movement, Rodney Croome, said Archbishop Porteous was distributing hate and prejudice.

This is what the leaders of the same-sex marriage movement think of the Bible.

The consequences for all Australians are real …

The third reason to vote “no” is to uphold the truth about gender. Justine Greening, the UK Minister for Women and Equalities recently said men being able to identify as women with the stroke of a pen was the next “step forward” since same-sex marriage was legalised in 2013.

In London a Jewish school has failed successive education authority inspections and is in danger of closing because it refuses to teach children that their gender is fluid.

In Ontario Canada, a Greek Orthodox father, Steve Tourloukis, lost his bid in the Supreme Court to have his children exempted from radical LGBTIQ sex education.

The consequences for all Australians are real, and we have a responsibility to be informed. Australia is a participatory democracy.

If we are silent about basic issues of justice for children, future generations will condemn us. When your postal vote arrives in the mail from 12 September, please participate and vote “no”.

Lyle Shelton is Managing Director of the Australian Christian Lobby and a Director of the Coalition for Marriage.