Fifty years ago, the Supreme Court effectively legalized abortion with its Roe v. Wade decision. Seven months ago, the Court took those rights away. Since the decision in Dobbs v. Jackson, antiabortion legislators have pushed state-level laws that try to ban abortions at earlier and earlier points in pregnancy. With some of these laws, legislators want to make abortion illegal as soon as an embryo has detectable cardiac activity. These so-called “fetal heartbeat laws” and their underlying talking point that abortion “stops a beating heart” are not only scientifically inaccurate, but they are also morally unsound.

As high-risk pregnancy experts, we appreciate that seeing or hearing cardiac activity is a meaningful moment for many people who are pregnant, and we share the joy of our patients who have a desired pregnancy. Two critical questions arise, however: Should a flicker of cardiac activity on an ultrasound limit options available to pregnant people, particularly those who desire or need to end their pregnancy? Furthermore, is a beating heart either a necessary (essential) or sufficient (adequate) standard upon which policy makers and cultural influencers such as antiabortion groups can decide the moral and legal status of either a human or a fetus? We follow the criterion for moral status used in bioethics—an entity “vulnerable to wrong or wrongdoing”—and legal status is defined as the rights granted to that entity.

With decades of experience between us as physicians helping our patients grapple with the decisions a complicated pregnancy can present, our answers to those questions are “no” and “no.”

Heartbeat bills are based on the work of an antiabortion, anti-LGBTQ, 2020-election-denier activist named Janet Porter, who has been named the “godmother” or “crusader” of the heartbeat movement. Those behind this movement believe that life begins at the onset of cardiac activity. The group Faith2Action first introduced this antiabortion legislation in 2011 in Ohio, sending heart-shaped balloons to lawmakers and bringing pregnant women to have the fetus “testify” via ultrasound exam. Since that time, multiple states have passed bills based on this model legislation, including Alabama, Georgia, Kentucky, Louisiana, Missouri, North Dakota, South Carolina and Texas.

But this belief is scientifically incorrect.

The cells in the embryo that will become the heart begin developing three weeks after fertilization (which we call week five because clinical dating of a pregnancy is based on the pregnant person’s last period). Researchers studying heart function have grown these cells, called myocytes, outside the body. With no heartlike structure, and no blood cells to support them, myocytes can still contract rhythmically.

From there, it’s a many-days-long process of biochemical reactions, cells passing molecular signals to one another and then assembling into loops via some of those signals, and finally, the start of electrical impulses before the organ becomes a coordinated heart capable of propelling blood. As early as five to six weeks after fertilization, before these structures resemble or function like a recognizable heart, we can use ultrasound exams to see the rhythmic motion of the early heart cells as they respond to electrical activity. It’s not until clinical week nine that we can see a recognizable four-chamber heart.

It’s these weeks of early development that are the target of antiabortion “heartbeat” laws, legislation that misses a critical concept: a beating heart is not the only factor that determines legal status, moral status and personhood.

But this doesn’t matter to antiabortion legislators, who place more value on the outcome of a pregnancy than the person experiencing it. Speaking about the heartbeat bill he authored, Texas state senator Bryan Hughes has said, “The heartbeat is the universal sign of life.” The legislative director of the group Texas Right To Life has argued that “the heartbeat is a morally significant biological moment where we can detect whether someone is alive or not.” These statements are wrong. Examples from other areas of medicine tell us that a human heartbeat is neither a necessary nor a sufficient criterion upon which to base complex ethical decisions.

First, having a heartbeat is not necessary to retain the full moral status of personhood. In some heart surgeries, for example, the surgeon needs to chemically stop the heart to move and fix the tissue. In other situations, when the heart can no longer pump blood, cardiac assist devices replace it. These people have no heartbeat, as we would traditionally define it, yet no one would argue that they don’t retain their usual legal and moral status. They have the same rights as someone whose heart is beating.

And in a heart transplant, where a person’s heart is taken out of their body and a new one put in, that person not only has no heartbeat for an extended time, but briefly, they have no heart. No reasonable person would argue that in such a situation, the transplant recipient was no longer entitled to the same rights and protections as any other person. So, no, a heartbeat is not necessary for anyone to have the moral status of personhood.

To illustrate that a heartbeat is not a sufficient criterion to completely determine legal or moral status, consider examples in which a human has a heartbeat, but their moral status is compromised or nonexistent. Strict criteria exist for declaring brain death, and lack of a heartbeat is not among them. Thus, once a person is declared brain-dead, they do not retain the same moral and legal status as other people, despite having a heartbeat.

It is at this point that clinicians may start recovering organs (in the event of planned donation), clear evidence of a change in moral and legal status; removing organs from a living person would cause harm and would be illegal. Warm-blood perfusion systems, which keep a donated heart warm and mechanically beating on the way to its recipient, provide another example. They are clear evidence that a beating human heart is not sufficient for the moral status of personhood. While breaking this transport system would be a tragedy, the person who did it could not be charged with murder.

Without dispute, a pregnant person retains their full moral status of personhood. Furthermore, declaring a single, electrically active and contractile organ, or the contractile cells it comes from, the stand-alone determinant of personhood is simply not valid. To force that pregnant person, who has unquestionable full legal and moral status, to continue a pregnancy and give birth against their will is clearly a gross violation of their personhood. People who are pregnant are the most capable of weighing the ethical questions involved in continuation or discontinuation of their own pregnancy. Abortion restrictions that place that decision-making authority with anyone or any entity beyond the pregnant person are anathema to evidence-based medicine and our responsibility to the people we treat.

This is an opinion and analysis article, and the views expressed by the author or authors are not necessarily those of Scientific American.