When it became clear Fiona's sister couldn't have kids, she made her a promise.
"Don't worry about that, I'll have the babies for both of us," Fiona, whose named we have changed for her privacy, said to her sister.
That was 14 years ago and, at the time, Fiona knew nothing about surrogacy.
"[My husband and I] thought about it and framed it as if we had a niece or a nephew who needed blood or a kidney or something like that, that we would, of course, step up and help," she said.
"Only later did I sort of start to think … that's maybe not quite the same thing."
While making her own family, Fiona began to have doubts about being a surrogate.
She had difficult births with her two children and experienced post-natal depression after the first.
Fiona grew more anxious about the process, but felt pressure to keep her promise.
"I came from a Christian background where women's role as mothers and nurturers was really put on a pedestal. And that was also an environment where choice was not really honoured.
"My thinking became 'just get through it, get to the other side', and then life will get back to normal."
About a decade after her initial "spontaneous offer", Fiona did get to the other side after becoming pregnant with her sister's baby and delivering at 37 weeks.
But life was anything but normal.
ABC podcast Ladies, We Need to Talk spoke to two women about their experiences of surrogacy, the fallout when things don't go to plan, and the joy it can bring when they do.
These are two individual circumstances and reflect the personal experiences of the women.
Surrogacy is medically, emotionally, financially and legally complex.
To learn more about the process, Surrogacy in Australia and Surrogacy Australia are helpful resources.
Warning: This story mentions suicidal ideation and self-harm.
Surrogacy in Australia
Altruistic surrogacy has been legal in Australia since 2010.
It's when the surrogate has their expenses covered with no other payment or personal profit made.
That's different to some places overseas where commercial surrogacy is an option.
It's estimated about 130 to 150 babies are born via surrogates each year in Australia. Most surrogacy arrangements are between family and friends, and records from family creation lawyer Sarah Jefford show about 20 per cent find each other online.
Katrina Hale is a psychologist who has been counselling couples going through the surrogacy process for more than a decade, meaning she knows both the legal requirements as well as what it takes emotionally to have a child for someone else.
"Anyone doing surrogacy in Australia, they need to go through mandatory counselling," Ms Hale says.
"It's called pre-surrogacy counselling. It's not just for surrogates, it's for the entire group of people who are doing the surrogacy arrangement."
Both parties must seek independent legal advice and often a surrogacy agreement is signed.
Ms Hale says prospective surrogates she sees will often go into the process underestimating their own needs.
"People come in with a simplistic view of surrogacy … they tend to underestimate their support needs because they want to give this as a gift."
'There was this physical grief in me'
At the time Fiona first offered to be a surrogate, she was living overseas and her sister was in another country with similar surrogacy laws to Australia's.
While her babies were still in nappies, Fiona filled in the paperwork to go ahead with the arrangement.
She'd hoped the process would take some time and she would be back living in Australia before things progressed. But the overseas surrogacy ethics board gave them the all-clear within six months.
Despite following the protocols, Fiona says red flags around her traumatic births and post-natal depression weren't raised.
After two embryo transfers, Fiona was pregnant. She began to feel detached from her body.
"I was getting progressively mentally [sicker and sicker]," she says.
"We got through the entire pregnancy without answering any of the questions that must be answered by surrogacy teams: Will the parents be in the room [for the birth]? What kind of physical contact will the surrogate have with the child after birth? How are we going to celebrate the day the adoption goes through?
"None of those questions had been asked or answered."
At 37 weeks pregnant, Fiona went to the emergency department and told them she needed to deliver the baby.
"I said 'I do not trust myself to walk out of here and not kill myself'.
"I need to stay. And you need to get this baby out of me. And then I was induced."
The birth was traumatic and because the baby was born in distress, Fiona didn't get skin-to-skin connection.
It's something Ms Hale says is crucial for surrogates who need to tell their post-birth bodies the child is safe and well.
"We have to bring Mother Nature along for the ride and transition those primal instincts which tell her post-birth, 'You just gave birth, you're supposed to be looking after a baby', so it's basically a gentle transition," Ms Hale says.
Fiona says she didn't realise how basic those needs are until she experienced birthing her sister's baby.
"There was this physical grief in me and that could only have been healed by holding the child that I had delivered," she says.
Fiona was able to hold the baby a few days later, but says she was so shut down she barely remembers the experience.
Ms Hale says surrogates need emotional support after the birth and that it should be planned for in detail.
"They've just walked barefoot across the Sahara desert to give someone a gift, so they need to know that they're appreciated and that their sacrifice is valued," she says.
'My intended parents were amazing'
Beth Williams had a starkly different surrogate experience to Fiona.
The 36-year-old has been a surrogate twice for same-sex couple Tyson and Dan, whom she met online.
Beth was a single parent raising two kids under 10 when she stared looking into surrogacy, motivated by wanting to help others who wanted to be parents.
After connecting online, the trio began "surro-dating". Six months in, Beth agreed to be a gestational surrogate for the couple.
Gestational surrogate means the egg used for the embryo is from another woman.
"For me personally, the idea of carrying a child that is my own genetics would feel like giving up my child whereas, being a gestational surrogate, I felt like I was able to maintain some separation there," Beth says.
Beth, Tyson and Dan went through counselling and sought independent legal advice.
After becoming pregnant, Beth says their relationships only strengthened.
They talked at length about what she would need during the birth and immediately afterwards.
And at 42 weeks, Beth was induced and baby London was born.
"We had always planned for me to have first skin-to-skin contact and so I had her placed on me and the boys were standing by just absolutely in awe," Beth says.
"It was such a beautiful thing to see that all of the counselling and legals and everything we'd been through had come to this moment where we'd finally done it.
"It was wonderful and being able to hand her over and say to them, 'This is your daughter. Meet your child'."
Beth says there were moments in the first week when she would wake and feel like "something was missing".
"Then I would call the boys and I'd go and see them," she says.
"You can prepare yourself mentally, but you can't prepare yourself physically."
Recently Beth gave birth to a younger brother to London.
'It cost me five years of my life'
Fiona says for a long time even thinking of her sister's name or the baby's name was painful.
"[It] was a really profound trigger for me, and I found it very, very had to think of them all without crying," she says.
After five years of therapy and healing, Fiona says she's in a better place.
"I am doing better. I'm enrolled in a master's of primary teaching. But that's the gap. That's what it cost me. It cost me five years of my life."
