When a woman agrees to become a gestational surrogate—meaning she’ll gestate an IVF-created embryo as it grows into a fetus—she and the commissioning parents will typically sign a legally binding contract. The terms vary widely from contract to contract and state to state, but the vast majority will include a clause allowing the parents to make decisions about abortion.

In surrogacy cases, the most common reason for abortion is multiple pregnancies. And of course, the likelihood of becoming pregnant with twins, triplets, and even four or five fetuses increases once IVF enters the picture—doctors will often implant multiple embryos at a time, to increase the chance that one will take. For various reasons—health, financial, or otherwise—parents whose surrogate ends up carrying multiple fetuses may request to “selectively reduce,” or abort one or more.

“That’s the main purpose of the surrogacy contract,” explains Jes Stumpf, the executive director at Vermont Surrogacy Network, an agency based in Burlington, Vermont. “To make sure that, should a decision about a termination arise, everyone is making the decision with full understanding. We only match carriers with intended parents who feel exactly the same way about not only abortion in general, but about hypotheticals such as reducing in the event of severe brain damage or physical deformities, or of course, if there’s multiple babies.”

But as a recent case illustrates, those contracts aren’t necessarily airtight. In January, Melissa Cook, a 47-year-old California surrogate currently pregnant with triplets, sued the commissioning father, a single 50-year-old Georgia postal worker, who wanted her to abort one of the fetuses. (The egg used to create the three embryos implanted in Cook was sourced from an anonymous, 20-something donor.) Cook, who is pro-life, filed a lawsuit in Los Angeles Superior Court, claiming California’s surrogacy law violates due process, as well as equal-protection rights guaranteed in the Constitution.

Cook says she wants to take all three fetuses to term, adopt the unwanted third, and collect her full surrogacy fee. She also wants the court to rule that her surrogacy contract is unenforceable, which would protect her from the consequences of breaching her contract and possibly allow her to keep the multi-thousand-dollar fee stipulated in her gestational carrier agreement.

“She’s trying to get the state of California, essentially, to not recognize the contract she signed,” explains Elura Nanos, a fertility attorney based in New York.            

Cook’s case has its own complicated caveats, but in a broader sense, it’s far from unique: As long as people have been using third-party reproduction, they’ve been grappling with novel legal and social questions about the meaning of parenthood, and what it means to set the terms of pregnancy and childbirth in a contract.

One of the best-known examples may be the much sensationalized “Baby M” case of 1986, in which a traditional surrogate—a woman who supplies the egg and carries the intended parents’ child—demanded physical custody of the baby after giving birth, and even went so far as to kidnap the child. The contract was ultimately deemed invalid, and the baby was returned to the intended parents, with visitation rights for the surrogate. (Cook’s lawyer is the same one who represented the surrogate that carried Baby M.)

The legacy of the Baby M case is that surrogacy agencies now recommend that surrogates do not supply genetic material, and they typically only accept women who have already given birth. The underlying belief here is that such carrier candidates are less likely to get too attached to the fetus(es) they’re carrying.

But because surrogacy contracts allow someone else to mandate that a woman abort fetuses growing in her body, surrogacy is much more than a legal issue—it’s a charged bioethical and political question, too. Who are the parents of the fetuses, and who gets to make such decisions? What are the implications for women’s reproductive autonomy?

Many of the reproductive-health experts I spoke to say it’s likely—based on Cook’s age (47, older than the typical age for a surrogate) and the fact that the intended father is being sued—that the pair did not go through a scrupulous agency, or that at least they were operating under poorly worded contract. But no matter how many legal issues you iron out ahead of time, there’s no way to legislate people’s emotional responses, says Elizabeth Reis, a professor of gender and bioethics at Macaulay Honors College at the City University of New York. “Yes, sure, you can sign,” Reis says. “But there’s no way to know how you’ll feel when you’re pregnant and ordered to reduce.”

I can personally attest to the unexpected feelings that can come with third-party reproduction. In 2009, I went through an agency in California to donate my eggs to anonymous parents. At 25, I donated out of financial desperation, so I found myself surprised by how overjoyed I was when the birth mother became pregnant with triplets. I was also devastated a few months later, when I learned via our agency liaison that she had lost two of the fetuses in utero. And when I learned much later that egg-donation recipients who become pregnant with multiples are often advised to “selectively reduce”—which very well could have been a factor in my recipients’ case—I found the idea unsettling, despite the fact that I’m fervently pro-choice.

But donors, unlike surrogates, aren’t asked to contractually agree to the possibility of abortion—because we don’t agree to any terms past our own donation. In fact, egg and sperm donors don’t even have a right to know what happens to their cells. The difference between donors and surrogates adds yet another wrinkle to already complicated ideas of what makes a parent.

“There’s so much interaction between a mother’s body and a developing fetus,” says Reis. “Nowadays, we understand that with surrogacy, you’re not just putting something in a toaster and having it come out, with no give and take. Now that egg donation is all over the place, we don’t want to think that because someone gave an egg, they’re a mother. But should these women—donors and surrogates—have some kind of relationship with the child?”

The father of Melissa Cook’s fetuses has stated that he believes singling one child out for adoption would be cruel, and thus he prefers to reduce. He has also cited health concerns for the developing fetuses. Cook, meanwhile, insists that all three embryos are healthy and viable. But does this mean those concerns the father has expressed about limited finances and the health of the babies should be discounted?

According to Melissa Brisman, the owner of the New York-based surrogacy agency Reproductive Possibilities, the babies legally belong to the father, but that doesn’t necessarily mean his wishes will win out. “Under California law, the commissioning father is the father, and there is no mother of the babies Cook is carrying,” she explains. “So if Cook doesn’t abort—and no court is going to force a woman into an abortion—he still gets to decide what happens. He could adopt the third baby out elsewhere, rather than allowing Melissa Cook to adopt him or her.”

Which spills into different territory—the question of whether or not the father should have to consent to be the parent of the unwanted child, even if he doesn’t raise it. “It’s still his DNA,” Reis points out. “Should he be forced to have [the baby] out there, any more than a woman should be forced to have her children?”

A major problem with assisted reproductive technology contracts is that they so often butt up against the right to privacy defined in 1973 with Roe v. Wade. “But while a surrogate has a constitutional right not to undergo the abortion—or to undergo one if she wants to—she has no such right to the payment stipulated in the contract,” explains Cyra Akila Choudhury, a law professor at Florida International University. And if the contract is effectively rendered void, it’s unclear if the surrogate would bear any responsibility for the children’s care after birth: “The question extends to whether she would be liable for any further damages, should these children be born with birth defects or anything like that. Most surrogacy contracts at this point don’t account for those hypotheticals.”

Nanos says that while surrogacy isn’t ethically a bad idea, it creates an absolute legal mess. “What if there had been six children and she said, ‘I’m pro-life and refuse to reduce them,’ and then as a result, they all died?” she asks. “Now what? Could the father have insisted she reduce to three? The law doesn't anticipate these kinds of Sophies Choice-type questions that people have to make once they’re creating babies in petri dishes.”

Some lawyers believe the outcome of this case could lead to tighter regulation of surrogacy contracts. (History shows that more stringent regulation, however, often drives people to seek surrogacy where it’s cheaper and easier, typically outside of the country.)

Melissa Cook is now expected to give birth to the triplets within seven weeks. On February 2, Cook’s lawyer, Harold Cassidy, filed a complaint in federal district court, attacking the constitutionality of the state’s right to enforce the selective reduction statute. Because this is a newly developing area of law, much remains unclear about the precedent Cook’s case could set. What seems more definite is the probability that, as assisted reproductive technology advances, many similar cases are bound to arise.