But most surrogacy agencies say they will work only with intended parents who cannot carry their own baby, as recommended by the guidelines of the American Society for Reproductive Medicine. So Chinese clients who seek an overseas surrogate to get around the one-child rule create a dilemma.

“We usually only take clients who have a medical need for surrogacy, but in December, we decided to bend that rule, for Chinese people, government officials, who would be in trouble if they break the one-child rule,” said Karen Synesiou, chief executive of the Center for Surrogate Parenting, in Encino, Calif. “We’re thinking of it as political surrogacy.”

Then, too, agencies and lawyers say, there has been a recent uptick in the number of clients seeking “social surrogacy” — that is, having someone else carry their baby so as not to damage their career, or their figure. And not all agencies follow the guidelines.

“We don’t feel like we should be the gatekeepers when it comes to that,” said Saira Jhutty, chief executive of Conceptual Options, a California agency.

Final Hurdles at Home

For all the intimacy of carrying a baby for someone else, there is no template for the relationship between intended parents and the woman who will bear their child. Most contracts contain a clause requiring confidentiality unless both parties agree otherwise. And most stipulate that there will be an abortion if the fetus has serious defects, or a reduction in case of triplets or quadruplets. While no court would force a woman to have an abortion, lawyers say, a surrogate who refused to honor the agreement, and proceeded to carry a baby to term against the intended parents’ wishes, could perhaps be made to pay the costs of rearing the child, under the legal concept of wrongful birth. As surrogacy spreads, lawyers say, litigation over such issues may erupt.

For those from abroad, getting an American-born baby home can involve tangled immigration problems. Some countries require a new birth certificate, a parental order or an adoption. Some will not accept an American birth certificate with two fathers listed as the parents. Occasionally, a baby can be denied entry into the parents’ home country.

But international law is catching up with social practice: On June 26, in a case involving two sets of children born to American surrogates, the European Court of Human Rights ruled that France had violated the European Convention on Human Rights, and undermined the children’s identity, by refusing to recognize their biological father as their legal parent, easing the way to French citizenship.