Commercial surrogacy, which is banned in most parts of the world, is a growing enterprise in India, where it is relatively cheap. However, the question of whether it is ethical has triggered a lot of debate.
Many couples opt for surrogacy if they cannot have their own children
Just as there are different reasons why couples cannot have children, there are different reasons why women might choose to become surrogate mothers, says Dr Sheela Saravanan, an independent researcher based in Bonn.
"One of the primary reasons is the money factor. If this were taken away I don't think anybody would choose surrogacy."
A surrogate mother in India is usually paid between 2,500 and 4,500 euros for carrying a pregnancy. If she gives birth to twins, she usually receives 25 percent more.
Manji Yamada was born to a surrogate mother at a hospital in Jaipur in 2008
"Abroad it's more difficult to find a surrogate mother," Saravanan adds. "They are more easily available in India where there is a big supply. They are also more naive I would say and less knowledgeable about their rights."
A surrogate should already have given birth
According to the regulations at Indian infertility clinics, a woman can only be a surrogate if she has already had children and knows how it feels to be pregnant. She should also be healthy and between 20 and 35 years old.
Some research has found that surrogate mothers do not usually bond with the babies they later hand over because they are emotionally prepared. However, there is also evidence that some surrogate mothers suffer depression after handing over the babies they have carried in their wombs for nine months.
So far no children have come looking for their real mothers because commercial surrogacy is still in its early stages. However, couples who have adopted children carried by surrogate mothers sometimes fear this could be the case and usually avoid contact with the biological mothers, says Dr Sheela Saravanan.
Right now the oldest children are four years old, she adds. "So it will be at least 10 years before children come searching for their real mothers."
German government does not support surrogacy
The German government does not support surrogacy and does not consider it legal when German couples adopt babies that have been carried by surrogate mothers.
A group of surrogate mothers in India
Advocates of surrogacy say that it is a win-win solution: Women who cannot have children are happy to have a healthy baby and surrogate mothers can earn some extra money with which to support their own families.
However, Rahul Ranadive, a researcher and film producer who has made a film about surrogacy thinks it does not solve the problems at all and that it should be banned.
"I see surrogacy primarily as a failure of the Indian state to address poverty and its ramifications. However, ethics, maternal bonding and fair trade in the globalized world are all connected with this issue."
Unless it is banned, the Akanksha Infertility Clinic in Gujarat will continue supporting couples who want to have children and women who want to carry them.
250 babies have been born there since 2005 and there are hundreds of couples and potential surrogate mothers on the waiting list.
Author: Julia Thienhaus
Editor: Anne Thomas