Did a U.S. surgeon general come up with the idea of the notorious Tuskegee syphilis experiment?

Hundreds of black men were tricked into volunteering as human guinea pigs. For 40 years, no one stepped in to stop it. That was the point of the experiment.

U.S. government doctors told Alabama sharecroppers suffering from syphilis that they had "bad blood" and duped them into enrolling in the Tuskegee Syphilis Study. Then, the doctors observed the men – without administering treatment – as the disease progressed.

Participants were offered $50 to pay for their own burial. Some unknowingly infected their wives and children.

The now-infamous study didn't end until after it was exposed July 25, 1972, by a 23-year-old Associated Press reporter who was tipped off by a government whistle-blower from San Francisco.

Another quarter century would pass before President Bill Clinton invited the few remaining survivors to the White House and publicly apologized for the "shameful" and "clearly racist" medical research.

"Why in the hell did they let all these people die when they already knew what the results would be? It makes no moral sense to me," said Jean Heller, the AP reporter who broke the story, in a recent interview. "When penicillin came along, why didn't you say, 'That's enough,' and give it to them and let them get well?"

Doctors say the study still reverberates today, sowing mistrust and suspicion in some disadvantaged communities.

But who exactly is culpable? Whose idea was it?

Most historians and medical scholars pin the study – formally known as the "Tuskegee Study of Untreated Syphilis in the Negro Male" – on Taliaferro Clark, a relatively obscure physician who in 1932 headed the venereal disease section of what was then the U.S. Public Health Service.

But Allen Hornblum, a Philadelphia author who has written about human experiments at Holmesburg Prison, says archived records indicate that a much more prominent figure in American medical history –  a World War II-era surgeon general – was the study's driving force.

In a new essay, Hornblum and coauthor Gregory Dober argue that Clark stole the idea of a Tuskegee nontreatment study from Dr. Thomas Parran Jr., a medical pioneer who graced the cover of Time magazine in 1936.

"We argue that if it wasn't for Parran, there never would have been a Tuskegee Syphilis Study," Hornblum said. "He is the intellectual godfather, the architect of the study."

Parran was anything but obscure. He helped draft the Social Security Act for President Franklin D. Roosevelt and became the nation's sixth surgeon general in 1936. Parran Hall, the building that houses the University of Pittsburgh's Graduate School of Public Health, is named after him.

The unpublished essay is titled "Masterful Inaction," the term Parran used in 1931 – more than a year before the start of the Tuskegee experiment – to describe a syphilis study in Oslo, Norway, that the authors say inspired him.

"We're upsetting the historical apple cart here," Hornblum said. "This is the most notorious experiment in American history. It's been long agreed upon that Taliaferro Clark initiated it. But the genesis of it actually precedes Clark."

Reuben Warren, director of the National Center for Bioethics in Research and Health Care at Tuskegee University, said that, if true, the development is significant.

"There has been so much that has occurred that has been unclear," Warren said.  "New facts bring new understanding. The surgeon general is the chief medical officer for the country. If it proves to be a valid revelation, I think it's important."

The authors' conclusion runs against that of Bad Blood: The Tuskegee Syphilis Experiment, a 1981 book in which James Jones called Clark "the father of the experiment." And that of Tuskegee's Truths: Rethinking the Tuskegee Syphilis Study, published in 2000 and edited by Susan Reverby, in which Clark is described as "the man who conceived the non-treatment study."

But Parran may have pushed for such an experiment first. In a January 1932 memo, Parran wrote of Macon County, Ala: "If one wished to study the natural history of syphilis in the Negro race uninfluenced by treatment, this county would be an ideal location for such a study."

Six hundred black men, mostly from Macon County, were enrolled in the study – 399 with syphilis, and 201 as a control group without the disease, according to the Centers for Disease Control and Prevention.

"As great a mind as he was, he had a moral blind spot," Hornblum said of Parran. "The doctors just waited for them to drop dead so they could do the autopsy."

In 1948, Parran became the first dean of the University of Pittsburgh's public health school. He died in 1968, and the following year, the building housing the school was rededicated and named in his honor.

"The school and the university recognize both the troubling issues of Dr. Parran's legacy, and that there were also great positives in his work," the university said in a statement, after Pitt officials were provided with a copy of the latest Parran essay.

"We deal with these issues in open public discussions and incorporate his impact on public health – both positive and negative – into our presentations of that history for students and the general public," the statement said. "We have held public lectures regarding Dr. Parran in the past and expect that new findings will become a part of future presentations."

The school "has no immediate plans" to change the hall's name, according to the statement.

In 2013, the American Sexually Transmitted Disease Association changed the name of the lifetime achievement "Thomas Parran Award" to "The ASTDA Distinguished Career Award" after news came out that Parran had approved secret syphilis tests in Guatemala. American doctors deliberately infected hundreds of Guatemalan prison inmates, mental patients, soldiers, and others.

"It was very gut-wrenching," Bradley Stoner, the association's president at the time, said in a recent interview. "But we felt like for the sake of the field we couldn't continue to keep the name on the award."

Stoner said Pitt faces a "similar situation" with Parran Hall, and compared it to Yale University's decision in February to rename a college that had been named after John C. Calhoun, who promoted slavery.

"I think that's for the University of Pittsburgh to decide," Stoner said of a name change.

Stoner and others said they have reservations about placing blame for the Tuskegee study solely on Parran.

Before penicillin, some treatments for syphilis – including arsenic and mercury – were toxic and potentially more harmful than the disease itself. "It's not surprising to me that someone would say, 'Let's not treat people and see what happens,' " Stoner said.

Reverby, a Wellesley College professor who uncovered the Guatemala study and has written extensively about Tuskegee, questioned the usefulness of Hornblum and Dober's essay – or of distilling the study down to a "simple story about race."

"They really thought they were doing something important," she said of early researchers. "That's where it gets complicated. These guys saw themselves as generals in a war against this disease, and they thought society had given them the right to say who lives and dies in the interest of winning the war."

Paul Lombardo, a Georgia State University law professor who has written about bioethics and eugenics, said that demonizing Parran and stripping his name from buildings and awards isn't necessarily the best approach.

"I'm all for smoking out the bad guys, but there's a real problem when you start changing the name of everything," Lombardo said. "There isn't any question that Parran's legacy is tied to Tuskegee and Guatemala, but he is also the guy who gets people talking about syphilis and gets treatment and funding for syphilis."

Lombardo and Reverby said they would support leaving Parran's name up at the University of Pittsburgh, but adding a plaque that also explains that he was involved in unethical medical research.

Lillie Tyson Head agrees. Her late father, Freddie Lee Tyson, had congenital syphilis and was part of the Tuskegee study. She now heads Voices for Our Fathers Legacy Foundation, an organization for descendants of the study's subjects.

Head, who lives in Virginia, had not yet read the Parran essay when reached last week. But changing the name of the Pitt building, she said, would be attempting to erase history – and the lessons learned.

"A lot of wrong has been done to a lot of people," Head said. "Let the building stand, but make sure you have the history behind him and what he had done. You have to tell the history and the impact that it had on generations. Spell it out and tell the truth."