The case of an Australian couple accused of abandoning their child with his Thai surrogate mother after discovering he had Down syndrome — and taking home his healthy twin — has turned global attention to the murky underworld of international surrogacy.

Such cases have raised ethical and legal dilemmas, which experts say are the inevitable consequences of an unregulated multibillion-dollar industry dependent on impoverished women in developing countries providing a “product” — a child — so desperately wanted by would-be parents in wealthier nations.

In Baby Gammy’s case, which made international headlines this month, the boy’s Australian parents are claiming that the Thai surrogate mother, Pattaramon Chanbua, refused to release the child into their custody and that they lacked the legal right to force her to do so.

Pattaramon said she was not initially informed that the child had Down syndrome even though the doctors, the agency brokering the surrogacy arrangement and the child’s parents knew when she was four months pregnant.

She said the agency waited until the seventh month to ask her — at the couple's request — to abort the fetus, which she refused to do because she believed it would be a sin. Instead, she asked the agent for 40 percent more money. In the end, she said she was paid only half the agreed price.

Since then, Pattaramon has raised more than $200,000 through an online fundraising campaign initiated by an Australian charity, after heavy media coverage. Among the details that have emerged about the situation was that man reported to be the father of Gammy is a convicted child sex offender.

Even before Gammy’s case entered the international spotlight, the legal challenges of transnational surrogacy prompted the Hague Conference on Private International Law, an intergovernmental organization, to begin investigating commercial surrogacy in 2011. Earlier this year, the organization issued a report with its findings and a set of recommendations for policymakers.

The report's findings are the subject of a three-day forum to be held this week at The Hague, where about 100 policymakers, scholars and activists from 27 countries will meet to discuss ways to improve international standards on commercial surrogacy.

Days after the Baby Gammy controversy erupted, another case emerged in Thailand, involving the discovery of nine surrogate babies who allegedly share one biological father, a 24-year old Japanese citizen. It remains unclear why the man chose to have so many children.

Another recent case involves an Australian couple convicted in a U.S. court in 2013 of making child pornography with a boy they adopted after paying a Russian woman $8,000 to be their surrogate in 2005.

But even in straightforward surrogacy arrangements, in which the would-be parents have unblemished records and the child goes to a loving home, the complexities of international surrogacy raise legal questions. Should a sperm donor be considered the legal parent? How does the law regard a mother who gives birth to a child who is genetically unrelated to her? Can a contract require a surrogate mother to submit to an abortion if the intending couple wishes? Is the child a citizen of the country where he or she was born or where the intending parents — the industry name for parents who seek a surrogate — reside?

All these considerations represent new frontiers in international law because existing laws simply don’t cross over into this area well. As one expert put it, paying a woman to carry someone else’s child “is not like renting out an apartment.”