Gretel Killeen's heartfelt message to the children of regretful mothers.

The Project tonight covered a topic rarely spoken about publicly: mothers who regret having children.

Following an online appeal, the Channel 10 program said it had been “overwhelmed” with stories from women who said that, while they loved their children, they also felt as if they’d made a mistake by bringing them into the world.

As mother of two Renee told the program, “I do not resent my child, but I do I resent that having a child did essentially trap me… I’ve never experienced what it’s like to be free.”

But as the segment wrapped, guest panellist and mother to two adult children, Gretel Killeen, turned to the camera to deliver a heartfelt, earnest message to the audience.

"I want to say to any kids out there watching, while it is hard raising a lot of you, raising my children was the happiest years of my life," the 54-year-old said.

"I raised mine as a single mum. It was really bloody hard, but I never regretted it. I don't want children watching this thinking that they're not bringing joy to their families.

"It is hard and support is important and recognising women's roles... I know the battles; I've fought them. But it was worth it."

Host Carrie Bickmore referenced messages The Project had received from women who'd had children for the sake of their now-failed marriages, those for whom the idea of motherhood proved better than the reality, and those who had simply never wanted children in the first place.

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While Killeen said she sympathised with and supported women in such a situation, she also urged caution.

"Whether a father stays or goes, or whether it's a pregnancy that was unintended, whatever it is, the children are the innocent ones here," she said.

"While I support all women - and there are various organisations if you're finding it very tough as a mum - while I support all of that, we have to be careful also we're not romanticising what we don't have.

"Many girls don't have children who yearn to have them."

If you're struggling, crisis support is available 24 hours a day via Lifeline. Please call 13 11 14.