An Australian woman has given birth to her own grandson.

A mother from Queensland has given birth to her grandson, after her daughter Alice, 25, was told that due to her childhood cancer, she would be unable to carry a baby full term.

Theresa Hohenhaus, 46, says it was “the best experience of my life,” reports 7News,

Theresa is already a mother-of-five, and became a surrogate to Alice at 45, when she was implanted with her daughter’s fertilised egg. There was a 50 per cent chance of pregnancy.

“I was told I couldn’t carry any more,” Alice Hohenhaus told 7News Brisbane.

“We were just sitting there and my mum turns to me and goes ‘I’ll carry your baby’.”

“I just looked at her and I said, ‘Pardon?'”

But Theresa said “after everything Alice has been through, it’s something I just had to do.”

Luckily Theresa, who has fostered 50 children, became pregnant almost immediately.

"It was amazing and every appointment and scan from then on we went to together and cried together... we are very very close," Theresa told Daily Mail Australia. 

The pregnancy wasn't always easy, with Theresa experiencing eight and a half months of morning sickness. But on June 2nd, she gave birth to a healthy baby boy named Parker James.

"I was worried about how I would cope when I had him but I had him naturally and afterwards they place him on my tummy and I had the first cuddle while Alice cut the cord.

"It was so beautiful. I was worried about handing him over at first and Alice was worried about how she would cope seeing me in so much pain. But we both made it through and it is a moment I will honestly cherish until I die."

Alice has a second, final frozen embryo in storage, so the question now is whether the family will choose to give Parker a brother or sister.

"I would absolutely do it again," Theresa said.

"People are worried about the effort but I am in good health and it would be so lovely for Parker to have a brother or sister... I don't think we would donate that last embryo."

This isn't the first time Theresa has been asked to have a baby for Alice. When Alice was diagnosed with cancer at age four, only to have it aggressively return at nine, her brother James was conceived to provide bone marrow to save her life. It worked.

However, Alice was told that the full body radiation she endured meant scar tissue would make it difficult to conceive, but much to Alice's surprise, she fell pregnant at 23. Tragically, she miscarried at 15 weeks.

Discussing the experience, Theresa told Daily Mail Australia, "I thought I was too old and Alice didn't want me to do it at first but I had already almost lost Alice twice before - she hemorrhaged during her pregnancy and it was touch and go there for a while."

"I would do anything for my kids and it truly is worth every bit of it to see Alice so happy," she said.