Anal exams are performed by police in many countries that criminalize homosexuality — and they base their work on 150-year-old European science. BuzzFeed News' J. Lester Feder and Maged Atef report from Cairo.

Maged Atef/BuzzFeed Dr. Maged Louis in his office in Cairo.

CAIRO — When asked to explain what Cairo's medical inspectors look for when they examine someone who's been arrested for homosexuality, Dr. Maged Louis picked up a pen and started sketching an oval with sharp points on both ends. "The shape of the hole will change," he said. The anus "won't be normal any more and will look like the female vagina." More than 150 people have been arrested on charges of homosexuality since President Abdel Fattah el-Sisi took power just under two years ago, the largest roundup of alleged LGBT people in more than a decade in Egypt. Anal exams are a routine part of the investigation in such cases, and Louis has a role in overseeing all of them. He is the deputy director of the Justice Ministry's Forensic Medical Authority, as well as the chief of forensic medicine for the Cairo police district. "First we make them take the prostrate position — the position that Muslims take when they pray," he said in an interview with BuzzFeed News. The tests are intended not just to determine whether someone has ever had anal sex, but also to detect "chronic homosexuals," because the letter of Egyptian law only criminalizes men who engage in "habitual debauchery." Louis said that he believed that in addition to their elongation, the anuses of "chronic homosexuals" also don't clench when touched or don't contract as tightly. They are smooth and lack the "corrugations" — wrinkles — found on "normal" anuses, he said. And though he denied that examiners penetrate subjects under examination, he also said they can detect a "chronic homosexual" if his anus can accept larger objects. "A normal man's anus can't take more than one joint of the small finger," he said. International human rights and medical experts dismissed Louis's checklist as having "no medical basis" and being "categorically not true." Most of those interviewed by BuzzFeed News couldn't contain their shock before all of the criteria were listed. "I think you heard my laugh — I think that says it all," said Dr. Joel Palefsky, a professor at the University of California San Francisco specializing in anal cancer who is president of the International Anal Neoplasia Society. "We run a clinic where we do anal examinations of thousands of patients ... Never in my 20 years of doing this have I seen an anus that looks like a vagina." Human Rights Watch and other advocacy organizations have long denounced such anal exams — which are routine in several of the world's roughly 80 countries that criminalize sodomy — as a form of torture that violates international law. Medical leaders in some of the countries where these exams are used have called for their abolition, such as in Lebanon. But Louis was incredulous that anyone could doubt his inspectors' work. "All of what I said is science and written in books," he said. "Doctors all over the world know that." The idea that inspectors are intentionally fabricating evidence because of their own homophobia isn't what makes these exams so disturbing — though that does sometimes happen, according to defendants' accounts. It's that beliefs about homosexuality are leading doctors — some of whom have done extensive (and horrific) research into perfecting diagnostic techniques — to believe that what they are doing is science.

Amir Nabil / Via AP Men who were arrested by police looking for gays at a Cairo public bathhouse hide their faces after being acquitted.

One of the modern pioneers in anal examinations in Egypt was Dr. Aymen Fouda, Louis' predecessor as deputy director of the Forensic Medical Authority, who went on to become chief medical inspector from 2005 through 2007. During a 2003 interview with Scott Long, then-director of Human Rights Watch's LGBT program, Fouda said the exams were based on techniques developed in Europe. "In this kind of investigation there are six criteria which were established by the celebrated Frenchman [Auguste Ambroise] Tardieu," Fouda said, referring to the 19th-century forensic doctor who published a book in 1857 called The Forensic Study of Assaults against Decency. In the book, Tardieu spelled out six "characteristic signs" of "habitual pederasty," which included those described by Dr. Louis as well as sores and fissures. But, he wrote, "[t]he unique sign and the only unequivocal mark of pederasty" is an "infundibuliform" — or funnel-shaped — anus. Fouda told Long that forensic experts were working on developing "new, advanced methods" to detect homosexuality "involving the use of electricity." Fouda had co-authored a 1998 study published in a journal published by the Egyptian Society of Forensic Medical Sciences that experimented with inserting hypodermic needles into the muscle of the anus in "unanesthetized humans" which claimed to demonstrate that gay men's anuses conduct electricity at a different rate. Other researchers continued experimenting with related methods, including a doctoral student who defended a dissertation at Ain Shams University — one of Egypt's most prestigious — in 2003 entitled "Medico-legal Assessment of the Anal Sphincter Functions in Sodomists." Tardieu's theories were suspect in Europe even when they were first published, said Khaled Fahmy, a historian of Egyptian forensic medicine at the American University of Cairo who has studied its translation into Arabic. "Even back then this is a highly ideological book," he told BuzzFeed News, part of a "morals campaign" that was a response to events in Paris at the time. And he thought it "would be shocking" to the Egyptian public if it were widely known that courts were continuing to treat examinations as serious evidence that were based on science that was 150 years old. But, he speculated, they endure in part because they reinforce certain basic notions about homosexuality that circulate in Egypt: that it is like a disease, usually passed on to children through sexual abuse. "There is a belief that this abuse during childhood will leave a physical mark, and it leaves a mark on the anus," he said. "We now have a homosexual body — not only a homosexual character which is a defective character, but it has physical traces that a forensic doctor can discern." And though these anal exams now seem laughable in Europe and the United States, the belief that a detectable physical basis for sexual orientation persists into the 21st century. In 2010, the Czech Republic announced that it would stop subjecting gay refugees to a practice called "phallometry" or "penile plethysmography" — which involves attaching a pressure-sensing device to the refugee's penis while he is shown heterosexual pornography — after it was denounced as "degrading treatment" by the United Nations Refugee Agency. The same belief for a measurable sign of homosexuality also lingers in the hunt for a "gay gene," suggests Graeme Reid, the current head of Human Rights Watch's LGBT program. Though the argument that homosexuality is determined by biology has been very effective for the LGBT rights movement in the U.S. and Europe, Reid said, efforts to isolate a "gay gene" are also based on a simplistic, "flawed cultural assumption" about the biological basis of sexuality. "The idea that there is kind of one causation for sexuality seems absurd given what we know about the complexity of human sexuality," Reid said.

AP Photo/Philip Mark Special police officers rush some of 52 alleged homosexuals on trial into court in Cairo, Egypt, Wednesday, Nov. 14, 2001.