The U.S. Supreme Court's June 24 ruling ending federal abortion rights under Roe v. Wade could inspire groups that seek to protect embryos to urge greater restrictions on in vitro fertilization (IVF) and embryonic stem cell research, according to Henry T. (Hank) Greely, director of the Stanford Law School Center for Biomedical Ethics.
Assisted reproductive technologies such as IVF aren't constitutionally protected and neither is preimplantation genetic testing, which screens for certain traits and DNA-caused conditions in embryos that haven't yet been implanted in the uterus, he said in a recent interview prior to the landmark ruling.
The court's ruling doesn't ban these technologies, which assist people seeking to have children, but it is likely to inspire some groups and states to seek to preserve unused embryos or ban embryonic stem cell research, Greely said.
His paper about the potential short- and long-term impacts of the decision is in preprint publication and is expected to be published in the Journal of Law and Biosciences in the coming weeks. In the short term, the technologies that embryo-protection groups might seek to ban or limit might be an alternative for women who can no longer receive an abortion in their home state.
Prenatal testing currently can determine if the fetus has a serious DNA defect that would cause disease or disability; a woman can then decide whether to continue with or terminate the pregnancy. That choice would likely disappear in states that restrict abortions, Greely said.
But a genetic testing technique that is used during in vitro fertilization could be utilized to prevent IVF pregnancies with fetal abnormalities. Preimplantation genetic testing, or PGT, screens out embryos with DNA-causing birth defects before the embryos are transferred to the uterus. The procedure can determine with a high degree of accuracy whether an embryo would develop into a baby who might have one of a large number of conditions. The decision not to transfer an embryo with genes that could cause a disability, condition or trait isn't illegal in the U.S., he said.
In states where abortion is illegal, it's likely there would be an increased interest in using PGT. The embryos are screened while outside the womb and prior to implantation and pregnancy.
"I think some people, some couples will say, well, if we have an embryo for the pregnancy that would have a severe disability as a child, our state wouldn't allow us to abort it. So let's go through preimplantation," he said.
But Greely doesn't think using PGT will skyrocket after the court's abortion decision. The technique requires that prospective parents use IVF, which is unpleasant and risky due to egg harvesting, he said.
IVF is also expensive. Most couples seeking the technique do so due to infertility and the decision isn't made lightly. Anyone with enough money to afford IVF would likely be able to afford to travel to another state for an abortion, he said.
Greely thinks it is unlikely embryo-protection groups would advocate for any kind of legislation that has a negative effect on IVF, however.
"Americans like IVF; almost everybody knows somebody or will know somebody who's either gone through IVF or who's actually the product of IVF. Two percent of the babies born every year in the U.S. with the product of IVF, and particularly the wealthier people are, the more likely they are to have either used IVF or know somebody who uses IVF, and also, the more likely they are to be politically powerful," he said.
There's a certain sort of law Greely thinks might be politically viable: limiting the selection or deselection of an embryo for IVF for a specific reason such as race, gender or disability.
"We've already seen it in abortion state statutes. A lot of abortion laws ban abortion for the purpose of discriminating on race, sex or disability status. And some of them explicitly say Down syndrome status.
"I can imagine the disability community coming together with protection groups to try to pass laws banning using PGT to select against embryos based on race, sex or disability. The important part of that would probably be disability and maybe even with the focus just on Down syndrome, which has a very strong support group and has some political sympathy," he said.
There isn't much political support for eliminating embryos that would have a fatal disease, however, he said.
"There's a more attractive case for protecting embryos that might become people with Down syndrome compared to protecting embryos that might become babies who would die within a year from Tay-Sachs disease," he said.
The court's decision on Roe v. Wade could invigorate efforts to pass new legislation to protect embryos outside the uterus among people who believe embryos are viable far earlier than at the 15 weeks in the Mississippi case that challenged Roe v. Wade. Some groups have claimed that human life starts far earlier and even at fertilization, which would make, in their view, all embryos for IVF "viable" regardless of whether they are implanted in the womb.
In the normal medical standard of care, no more than two embryos should be transferred into a woman's uterus at a time to minimize the chances of multiple pregnancies, Greely noted in his paper.
Most IVF cycles produce more than two eggs. Prospective parents can choose to have the extra embryos frozen for possible later use, donated to other couples, designated for research or destroyed and discarded.
Some legislation advocated by embryo-protection groups could limit or change the practice, he said. With the exception of Louisiana, there are no limitations on destroying embryos that aren't implanted, he said, though some other states have considered the legislation.
"The only limitation that I know of is the Louisiana law where you're not allowed to destroy embryos. So leftover embryos are kept frozen indefinitely in IVF clinics there," he said.
Legislation could lead clinics to build facilities to freeze and store unused embryos in perpetuity, he said, adding that the Louisiana law hasn't caused IVF clinics to close.
Embryo-protection groups might also try to get a law passed that's similar to a 2004 Italian law, which was subsequently limited by a court decision, Greely noted.
"They said you have to transfer for possible implantation every viable embryo you make, which means in Italy they typically only make one or two embryos at a time.
The embryo-protection groups "might try that, but all that would do is make IVF more difficult or expensive, and I don't think there's going to be political support for it. I don't think there'll be enough political support for it for people to adopt it," he said.
Greely noted that there could potentially be a significant change in embryo research as opposed to clinical treatments in an IVF clinic.
"Actually, embryo research in particular has really nothing to do with Roe v. Wade. As a matter of law, Roe v. Wade never protected embryo research, but I think it's connected in terms of the political dynamics after the death of Roe v. Wade," Greely said.
There's a good chance that at some stage, states will pass laws that eliminate human embryo research, in part because it is a huge issue, he said. Embryonic stem cells are taken from embryos created and then not used for pregnancy at IVF clinics.
"Twenty years ago, a number of states banned it; a number of states like California encouraged that research. But research into Type 1 diabetes and other major diseases has been disappointing.
"I think it has been useful, but there have been no miracles from it so far," he said.
The discovery in 2007 of a method to turn regular body cells into cells that can become any cell type in the human body makes the argument for using embryonic stem cells less compelling, he noted in his paper. Called induced pluripotent stem cells or iPSCs, these cells take away some of the urgency about using embryonic stem cells.
But iPSCs aren't exactly like human embryonic stem cells, Greely noted. Researchers would likely argue that human embryos are still required for research on embryonic development that would lead to ways for couples to succeed in having babies.
iPSCs might also play a role in the same types of research, since scientists have been creating "embryo-like things" or "embryo models" that provide more information about human embryonic development, he wrote.
How these laws might affect funding for embryonic research is also unknown.
The federal government has had little appetite for funding embryonic research and has refused to fund research that "destroys, discards, or knowingly subject(s) to risk of injury of death" embryos, Greely noted in his paper.
Yet, the federal government doesn't limit or ban the research itself; its actions have solely been about research it funds. Federal funds can be used for research on cells created from embryos that were destroyed somewhere else, he noted.
At least 11 states, however, have banned (or effectively banned) human embryo research on cells created from destroyed embryos that came from somewhere else, he wrote.
Some states allow such research, including California, Connecticut, Michigan, Montana and New York, Greely noted. California in particular continues to support stem cell research without a ban on the use of embryonic cells. In 2020, the state's voters passed Proposition 14 for $5.5 billion in bonds to advance the research.