Singaporeans desperate to start a family have gone to countries such as Malaysia, India, the United States and Thailand and paid six-figure sums for a stranger to carry their baby.
Those in the know say people from Singapore have been having babies through surrogate mothers for at least the past decade. And in recent years, Bangkok has become a popular place for Singaporeans to rent a womb.
One man who advertises surrogacy services is Mr Michael Ho, who runs Singapore-based Asian Surrogates. He told The Sunday Times: "Singaporeans like to go to Bangkok as it's nearby and costs about the same as Malaysia. The Bangkok facilities are world-class and doctors are very experienced."
But he fears that may change in the wake of the Baby Gammy controversy, where a baby boy with Down syndrome was born to a young Thai surrogate and allegedly abandoned by his Australian parents.
The case has attracted international attention, leading the Thai authorities to crack down on doctors who perform commercial surrogacy procedures.
"I expect my business to take a total hit as Thai doctors are now afraid to do surrogacy procedures, as they risk losing their medical licences," said Mr Ho. "I have to explore sending new clients to India or close down."
The 60-year-old described himself as a property agent who went into the surrogacy business as a "sideline" in 2006.
He charges his clients $49,000 and that includes the surrogate mother's fees - "slightly more than half" - as well as what he pays his Thai agents. The couples pay more for in-vitro fertilisation (IVF) treatments and other hospital charges.
He said he has been getting under 10 clients a year, mostly Malaysians and Indonesians. It was only in recent years that a few Singaporeans have used his service.
"Surrogacy is not widely accepted in Singapore and in this part of the world," he said.
While there are no laws that explicitly prohibit surrogacy in Singapore, Health Ministry guidelines state that facilities providing assisted reproduction services are not allowed to carry out surrogate arrangements.
Surrogacy is where a woman agrees to become pregnant and carry a child for someone else, usually for payment. In what is known as gestational surrogacy, a woman's eggs are fertilised with her husband's sperm through IVF and implanted into the surrogate mother's womb.
Couples usually resort to surrogate mothers if the woman is unable to conceive or carry a pregnancy to full term.
Mr Ho said that when he started his baby business, he sent his clients to Kuala Lumpur and Johor Baru for the surrogacy procedure. The surrogates were Malaysian and Filipino women, including poor single mothers.
But in 2008 the National Council of Islamic Religious Affairs in Malaysia issued a fatwa banning surrogacy. Mr Ho said after that, Malaysian doctors preferred not to perform the procedure, so he began sending his clients to Bangkok.
He said his Singaporean clients are well-to-do couples in their 30s and 40s, who had tried IVF many times but failed, and did not want to adopt a child.
The Thai surrogate mothers were often poor village women under 25 years old. His Thai agents would house and care for the women who need the money.
After adding the cost of IVF treatment, a couple using a Thai surrogate could easily spend $100,000 before having their baby, he said.
Fertility clinics in Bangkok were unwilling to talk about surrogacy in the wake of the Baby Gammy case.
Fertility clinics in India and the US were more forthcoming.
Dr Anoop Gupta, director of the Delhi IVF & Fertility Research Centre in New Delhi, said his centre used to get five or six couples a year from Singapore for surrogate babies.
Many were Indian nationals who had settled in Singapore.
But since the Indian government ruled last year that foreigners who go to India for surrogacy procedures must have medical visas, not tourist visas, he no longer gets any Singapore couples looking for surrogates.
To get a medical visa, the applicants must attach a letter from their government stating that it recognises surrogacy and the applicants will be able to bring the child born through a surrogate home as their biological child.
He said it cost US$40,000 (S$50,000) for a "baby guaranteed" programme at his clinic, where the man's sperm fertilises a donor's egg. The sum covers all medical and legal fees, as well as about $9,000 paid to the surrogate.
Some Singapore couples, meanwhile, have gone online to find surrogate mothers willing to bear their babies.
One man, a 31-year-old manager and Singapore permanent resident, told The Sunday Times he and his Singaporean girlfriend are hoping to find a surrogate mother through the website findsurrogatemother.com.
They think it will cost less to pay a surrogate directly, rather than to go through an agent.
His girlfriend is unable to have a baby because of a womb problem, he said.
So far, a German woman has contacted them via the website and offered to bear their child for 25,000 euros (S$42,000) and have the IVF procedure done in Thailand or Canada.
The man said they are seriously considering her offer and added: "Surrogacy is the only way we can have our own blood-related children."