The Olympics women's gymnastics tournament suggests that this is a sport coming to terms with its devastating recent history. Indeed, Simone Biles has been determined to make sure this is the case.

The superstar was assaulted by physician Larry Nassar, who pleaded guilty to criminal sexual misconduct in 2018, after sexually abusing more than a hundred young gymnasts under the guise of medical treatment. Biles decided to compete in Tokyo to force the Olympics to reckon with this history. “If there weren’t a remaining survivor in the sport, they would’ve just brushed it to the side,” she told Hoda Kotb in an NBC interview in April. “But since I’m still here, and I have quite a social-media presence and platform, they have to do something.”

That’s a lot of pressure. On Monday, Biles posted on Instagram, “I truly do feel like I have the weight of the world on my shoulders at times.” Soon after, she pulled out of the team final and then the women’s all-around competition, where she was the defending champion, to focus on her mental health.

The extent of the damage done, and not just to Biles, is mind-boggling. It raises the uncomfortable question that hangs over the gymnastic competition in Tokyo: how could this happen? How could a medical doctor regularly sexually assault children, sometimes with a parent in the room, and get away with it for so long?

The answer is a combination of the sport’s culture and the longstanding and contested practice of the pelvic exam.

Many gymnasts had given over their lives to the sport, enduring regimented starvation diets, long hours of training and multiple injuries in the hopes of becoming the next Nadia Comaneci or Mary Lou Retton. Especially given their age, they were in no position to understand that the “treatment” they were receiving, as Nassar cupped a breast or penetrated a vagina with his fingers, was not a medical procedure.

This confusion is nothing new. Ever since the introduction of the pelvic exam in the late 19th century, patients and doctors have struggled to understand and define the boundaries between preventive healthcare and sexual impropriety. This blurriness, in turn, resulted in opportunities for male doctors to exploit women and exert power over them under the guise of medical expertise.

A.F.A. King, professor of obstetrics at The Columbian University — which later became part of George Washington — in Washington, noted in his 1895 obstetrics textbook that a vaginal exam, while rarely needed, was necessary to determine whether a woman was in labour.

He offered guidance “to the young practitioner, who may experience some embarrassment with his first vaginal examination”. It was not necessary, he assured the reader, to “obtain verbal consent of the patient before instituting the examination”. Proceed “without hesitation as if consent had already been obtained”, he told them, adding that there was no need for “explaining your actions”. Silence was preferable. “The less said the better,” he emphasised. If women cried or resisted? “Proceed just the same,” he said.

This powerful message, which essentially enabled medical men to violate women’s bodies against their will, underscored the extent to which women were completely at the mercy of their doctors. They did not need to be informed of penetration, and they were not allowed to resist. It would take nearly a century to break the silence about the potential for abuse in the examining room.

Indeed, these misogynistic ideas persisted as pelvic exams became the norm during the first half of the 20th century.

During that time, the male-dominated field of gynaecology expanded to include “caring for women’s entire reproductive system in all its physical and psychological aspects”. Gynaecologists were encouraged to look not just for bodily abnormalities, but behavioural ones — for example, performing premarital pelvic exams to ensure that young brides were “stretched” enough and ready for the wedding night. Guiding young women through the mechanics of sex to ensure “marital stability”, gynaecologists established their position as moral arbiters during the postwar era.

By the late 1960s, however, the increasingly blurred boundaries between gynaecological procedures and sexuality became a focus of concern within medical education. Robert Kretzchmar, at the University of Iowa, believed that “gynaecology presents perhaps the most challenging doctor-patient encounter because of the sensitivity of the subject, the sexual overtones, and the anxiety to be coped with”. In 1973, a survey of 146 woman attending 41 medical schools in the US revealed the blatant practice of sexualising women patients in medical settings. One woman complained of “hearing men make remarks to the effect that the gynaecological exam must be titillating to perform”.

Health feminists in the 1970s drew increased attention to these problems, demanding reform in medical education and gynaecological practice to protect and respect women patients. They used a wide range of strategies to increase women’s control over their own bodies, including advocacy, education and the creation of alternative healthcare organisations.

Health feminists understood that the pelvic exam was not just a medical procedure. It was a window into a deeper, more meaningful set of questions about gender, medicine and power. “When I was a little girl I used to visit a man who made me remove all my clothes,” Ellen Frankfort, a former Harvard Medical School student, described in her bestselling exposé, Vaginal Politics. “Once naked, I would lie down as he commanded so that he could touch the different parts of my body and even insert his fingers or other objects into my openings.” Her first pelvic exam taught her that what a doctor did to a young woman in a clinical space was “exempt from the usual taboos”. It left her completely exposed, vulnerable and silenced. And it didn’t need to be that way. Any penetration, even by a doctor, should require consent, Frankfort argued, so that a woman understands what is being done to her and that she has a choice.

The procedure as we know it today carries the burden of its history; and confronting this history is essential to understanding how Nassar — an osteopath, not a gynaecologist — banked on the confusion about what separates a legitimate medical procedure from sexual assault to get away with his crimes for decades.

Whenever questioned as to why he would spend so much focus on the pubic region for a back injury, he offered a medical rationale: pelvic floor therapy, a procedure designed to treat pain and weakness in the pelvic muscles that sometimes legitimately includes internal palpation.

And yet, as Rachael Denhollander proved 16 years after Nassar inserted two fingers inside of her vagina with no warning and no gloves, Nasser was not certified to practise internal pelvic floor treatment. He was a fraud and a paedophile. Her testimony, along with more than 100 others, helped to establish that Nasser was not performing a medical exam, but something done for his own sexual gratification. Successfully divorcing the two enabled her and other survivors to fully understand that what had been done to them was indeed assault.

Nasser’s abuse went on for decades largely because he capitalised on the historically blurred boundaries between sex and medicine. Brave women such as Denhollander and Biles have broken that silence, but the cost they and others have borne is enormous.

• Wendy Kline is the Dema G. Seelye Chair in the History of Medicine at Purdue University and author of Bodies of Knowledge: Sexuality, Reproduction, and Women's Health in the Second Wave and Coming Home: How Midwives Changed Birth