The former frontrunner to succeed Nicola Sturgeon as Scotland's First Minister says she believes it is wrong to have children outside of marriage.
Kate Forbes - who has already sparked a backlash after saying she wouldn't have supported same-sex marriage - also said that religious rights must be defended if a ban on conversion therapy is introduced.
SNP leadership hopeful Ms Forbes, who is a member of the socially-conservative Free Church of Scotland, said in a TV interview that having children out of marriage "would be wrong according to my faith".
The Scottish Finance Secretary told Sky News' Connor Gillies: "It's something that I would seek to avoid for me personally, but it doesn't fuss me at all, the choices that other people make."
But pressed on her view, Ms Forbes: "In terms of my faith, my faith would say that sex is for marriage and that's the approach that I would practice."
But she said that if she took the top office, she wouldn't try to impose her views on others.
Ms Forbes sparked a furore only hours after announcing her candidacy by telling an interviewer that her conscience wouldn't allow her to vote in favour of same-sex marriage.
A string of backers withdrew their support, including Public Finance Minister Tom Arthur, Children's Minister Clare Haughey and Health Committee convener Gillian Martin.
Ms Forbes stoked further controversy by asking LGBT+ people to "afford the right to people of faith... to practice their beliefs".
The Scottish Government is committed to bringing in a ban on conversion therapy - defined as acts seeking to "change, suppress, or inhibit someone's sexual orientation, expression of sexual orientation, gender identity or gender expression" - by the end of the year.
The leadership hopeful described the practice as "absolutely abhorrent" - but said the "rights of other minorities" including those of faith, should be defended in any ban.
Ms Forbes said: "As somebody of faith, the concept of coercion is absolutely abhorrent.
"I strongly condemn the use of any coercion when it comes to people's sexuality or when it comes to people's faith.
"I would argue that in a pluralistic and tolerant society I would certainly defend to the hilt everybody's right to live and to love free of harassment.
"The conversion therapy bill hasn't been introduced yet as far as I know. But equally we should defend the rights of other minorities like people of faith, as well, when it comes to their freedom of expression, their freedom of speech and their freedom of practice.
"I think there's a way for a bill to respect that whilst at the same time ensuring that coercion has no place in Scotland."
Ms Forbes was hotly-tipped to take over from Ms Sturgeon following her shock resignation, and 24 hours ago was the 2/1 favourite.
But the row could prove costly, with bookmakers upping her odds to 5/2 as Mr Yousaf - who said he would "always fight for the equal rights of others" - overtook her at 2/5.
Just three candidates - including former community safety minister Ash Regan - have put their name forward to be First Minister after several high-profile figures including Angus Robertson ruled themselves out.
Things started to go wrong for Ms Forbes after she told The Scotsman: "I would have voted, as a matter of conscience, along the lines of mainstream teaching in most major religions that marriage is between a man and a woman.
"But I would have respected and defended the democratic choice that was made.
"It is a legal right now and I am a servant of democracy, I am not a dictator."
A senior member of her campaign team later told Scotsman journalist Alexander Brown that she had "f***d it".
But Ms Forbes said her leadership bid isn't over yet.
She told the BBC: "We have a large party membership, most of whom are not on Twitter.
"I understand people have very strong views on these matters. I think the public are longing for politicians to answer straight questions with straight answers and that's certainly what I've tried to do in the media yesterday. That doesn't necessarily allow for much nuance.
"My position on these matters is that I will defend to the hilt everybody's rights in a pluralistic and tolerant society, to live and to love free of harassment and fear."
Downing Street said Rishi Sunak was "hugely proud" of the UK being a diverse and tolerant country, but would not be drawn directly on Ms Forbes' stance on gay marriage.
"The Prime Minister has said before that he is hugely proud of the UK being a diverse and tolerant country," Mr Sunak's official spokesman said.
"He has spoken in the past about improving the lives of LGBT people and not wanting anybody in Britain to have to hide who they are or who they love."
Pressed on Ms Forbes' position, the spokesman said: "It's fundamentally a decision for members of political parties to decide who leads them. That's not something I'm going to comment on."
