Where do we draw the line between life and death?

You’d think that it would be simple to determine if someone is dead. But making the call can be fraught, especially when there are cultural, religious and legal definitions of death that conflict with the science.

The invention of ventilators and other advanced care has further complicated the definition of brain death, making it possible for a person without brain function to have a heartbeat and be breathing. “It’s a strange thing to have to accept that a person who looks alive is actually brain-dead,” Science News neuroscience writer Laura Sanders told me. “That relatively recent possibility opened the door for confusion.”

In this issue, Sanders reports on a new international effort to define brain death. Clinicians from around the world reviewed the existing data, which are slimmer than you might think, and then outlined a set of steps to take before declaring someone brain-dead. The guidelines are a big improvement, but the diagnoses can still be complicated, sometimes relying on inconclusive tests and steps that vary with the patient’s age.

And if it’s confusing now, get ready for even more challenges in the future. Advances in brain science and in technology may blur the definition of death further. And they may change life, too, in ways both good and bad. Scientists may develop new ways to treat diseases, but drugs and implants could also be used to control our thoughts and emotions, or even change who we are — the stuff of dystopian novels.

Sanders, who has a Ph.D. in molecular biology, is fascinated by the deep questions raised when science races ahead of society. In 2019, she covered the startling news that Yale researchers had restored cellular activity to pigs’ brains hours after the animals had been killed at a slaughterhouse (SN: 5/11/19 & 5/25/19, p. 6). “This gets at one of the most fundamental questions we have: What it is to be alive,” Sanders says. “As scientists get closer to understanding how the brain operates, they’re going to be able to start clarifying those limits in totally new ways. And that, of course, will raise more questions.”

Among them is whether people will agree to limits set by science and the law. When doctors declared Jahi McMath, a Black California teenager, brain-dead after a 2013 tonsillectomy, her parents challenged that decision. They drew support from religious and civil rights groups, and moved Jahi to New Jersey, which allows religious objections to the diagnosis. Jahi spent more than four years on a ventilator; the family’s attorney said she died in June 2018 of liver failure.

In this issue we dive into another scientific advance that prompts big questions — genetically engineering mosquitoes to combat diseases. After a decade of contention, officials in the Florida Keys approved releasing GM mosquitoes to fly freely in the United States for the first time, life sciences writer Susan Milius reports. The company that breeds the modified males says it addressed people’s concerns about environmental impacts. Harder to address is skepticism about corporations and governments tinkering with nature.

We’ll continue to explore these complex questions of how scientific advances impact our world. Stay tuned.

Nancy Shute is editor in chief of Science News Media Group. Previously, she was an editor at NPR and US News & World Report, and a contributor to National Geographic and Scientific American. She is a past president of the National Association of Science Writers.