An exam meant to determine whether a baby was born dead or alive is of “questionable value,” the National Association of Medical Examiners cautions. The paper follows a ProPublica report on how the test had been used against women accused of murder.

The nation’s largest organization for medical examiners has issued a warning about a controversial, centuries-old forensic test that has contributed to cases in which pregnant women have been charged with murder.

The premise behind the lung float test is simple: If a baby was born alive and then died, air from its first breaths would cause its lungs to float in a jar with water. If the baby was stillborn, the lack of air in the lungs would cause them to sink.

But the many critics of the test have long labeled it junk science and drawn parallels between the test and witch trials, where women were deemed witches based on whether they floated or sank.