The fraught world of UK surrogacy
In the UK you cannot pay for a woman to have your baby, regulation is loose and arrangements depend entirely on trust. Demand for surrogates far outstrips supply.
Sarah Jones has had six children - three with her husband, the others with three different couples who wanted children.
The youngest surrogate child, Elliot, is one-and-a-half. His parents are Michael Scott-Kline and Nick Scott, and he was conceived using Michael's sperm and Sarah's egg.
Sarah, 37, says the experience of being a surrogate mother can be "a bit of an emotional roller coaster".
"You meet up with a couple and you start getting to know them and it's like dating. You go out with each other and you meet each other's family because you are building a lifelong relationship with them." But she says that once the baby is born, "it's just the biggest high you could ever have".
"You get that feeling that you've created a family. And there's not very many things that you can say have changed somebody's life. You've got such a sense of pride."
There are two types of surrogacy - "straight" surrogacy, in which the surrogate is also the biological mother [with her own egg], and "host" surrogacy, in which the egg comes from another woman. Those hoping to have a child through surrogacy are known as the intended parents.
The recent case of Gammy, a baby with Down's syndrome born to a Thai surrogate and allegedly left behind by the intended Australian parents, showed the complexities of international surrogacy.
But in the UK surrogacy remains relatively restricted. It is a crime to advertise for a surrogate or to offer your services as a surrogate. It is also illegal to pay a surrogate a fee. Agencies recommend expenses only of up to £15,000 for medical bills, clothes and time lost.
Once a child is born the surrogate has no obligation to give him or her up. Until legal rights to the child are transferred using a parental order, the birth is registered with the surrogate mother's name and, if she's married, her husband's name - even if the husband isn't related to the child in any way. Only if the surrogate is unmarried can a biological father be immediately registered.
That's why trust is vital.
"When you feel the baby kick it's amazing," says Jones. "But you immediately phone the couple and say 'your baby's kicking me' and you pass that excitement on to them."
Media attention sometimes focuses on surrogacy cases that go wrong - though surrogacy agencies, not-for-profit bodies that allow surrogates and intended parents to network, say this rarely happens. Those involved say the real challenge is navigating the system.
Carol O'Reilly, 42, has three children of her own and five surrogate children. She also donated eggs to a friend.
Now she works for Childlessness Overcome Through Surrogacy (Cots) - one of the main British agencies - vetting potential parents and surrogates.
"The surrogate has to trust the couple to take the baby, the couple have to trust that the surrogate will give them the baby," she says. "If the surrogate decides to keep the child, she can. If the couple decide they don't want the child, they can walk away."
Surrogacy agencies cannot order the fullest criminal record (DBS) check, which are needed for fostering or adoption. But some cases are rejected following a more basic police check, or because the intended parents are not "in the right frame of mind".
"They think that they can just buy this child and run off into the sunset," she says. "You have to sort of say no, this is about surrogacy. This is about looking after the surrogate. She's not becoming your servant or anything else. She's actually here to help you."
Many intended parents want a surrogate who is already a mother, feeling there is less risk that they would want to keep the baby.
But the surrogates are the ones that get to choose the intended parents. And there are consistently more parents waiting than surrogates available. Cots has closed its membership because of a shortage.
The number of registered surrogacies has risen from just 83 in 2010 to a projected figure of more than 200 this year. That only counts those who obtain parental orders, though most parents are thought to do this.
The Department of Health says there are no plans to further regulate surrogacy in the UK. The only change on the horizon is that from April next year intended parents will have the right to maternity or paternity leave.
Surrogates say people tend to be baffled about why they would go through the physical and emotional effort of carrying a baby for nine months, only to give it away.
For Amanda Benson, it was a way to have a child whilst helping someone else. She chose not to raise a child herself mainly because she couldn't afford it.
"Surrogacy seemed the obvious thing to do," she says. "I've always wanted to have children, never had the opportunity, and I thought well maybe I could do it for somebody else.
"It's not as if for nine months I thought it was my baby and then suddenly it changed. All that time I've known it was for somebody else."
She chose a gay couple since she felt that "they'd be more accepting of having a woman in their family as well".
She had two children with them who she still sees - the kind of contact that is very much encouraged by the big surrogacy organisations.
Then she tried again.
"I found a really nice other couple and we tried for a while. And I got pregnant - and this was probably when I was 42 - but unfortunately the child had Down's [Syndrome]."
The couple didn't want to continue with the pregnancy, so the agonising decision was made to terminate.
"It's not my baby to keep," says Benson. "I would have preferred if they wanted to keep the baby, but I wouldn't want to have a baby that they didn't want."
The shortage of surrogates means some intended parents go abroad. Estimates suggest the numbers could be in the hundreds or possibly thousands, with a sharp increase over the past few years - though there are no reliable figures.
One popular choice for intended parents is India, where surrogacy is big business.
The fee - just a part of the total cost - starts in the region of £17,000, of which about one third goes to the mother and the rest to the surrogacy business she works for.
Bobby and Nikki Bains, a Sikh couple who live in Essex, went there after finding out Nikki could not have children. They wanted an Asian egg donor and an Asian surrogate, and it was hard to find either in the UK.
In India you need a legally binding contract before you start the surrogacy process. Surrogates can only be "womb carriers" - they cannot be genetically related to the baby.
"If the baby is disabled or even if you become disabled, who's going to be the next of kin, who's going to look after baby? All that is pointed out in the surrogacy contract," says Bobby.
He defends payments to surrogates, who are limited to carrying other people's babies twice.
"These surrogates in India or the ladies that want to do surrogacy know what they're getting themselves into. I think most people go to do a job. Most people go to work because they need the money."
More from the Magazine
Commercial surrogacy is estimated to be worth more than $1bn a year in India. While pregnant, some surrogate mothers live in dormitories - which critics call baby factories. They give childless couples the family they have longed for, but what is it like for the women who carry someone else's child for money?
Nick Scott thinks the UK could borrow a little from India, given the grey areas and lack of legal guarantees he's experienced. "We had a child who we looked after in everyday life but we had no rights over," he says.
"There can be more legally binding agreements before people embarking on a surrogacy journey. The processes are not fit for purpose in some cases."
Catrin Nye presents The Report: Surrogacy on BBC Radio 4, at 20:00 BST on 21 August - or catch up on BBC iPlayer
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