ABOUT SEVEN YEARS AGO, Christine Metz, a biomedical researcher at the Feinstein Institutes for Medical Research in New York, had an idea for a study of endometriosis, a painful disease in which the type of tissue that lines the uterus begins to grow on other areas of the body. Currently, a formal diagnosis requires an operation performed under general anesthetic. Metz wondered, among other things, if patients could be correctly diagnosed using a less invasive approach.

To recruit people for her study, Metz reached out to physicians, hoping they would ask their patients to participate. But the doctors balked. “’People told us, ‘Oh I can’t ask my patients to do something like that,’” she recalled, where “that” referred to providing samples of menstrual blood. “There was definitely a ‘yuck’ factor,” said Metz.