Tackling five myths about J. Edgar Hoover:

1. Hoover was a gay cross-dresser.

Despite rampant speculation — that Hoover was gay, a cross-dresser or had no sex life — the truth about his sex life is nearly impossible to pin down. Hoover was married to his job and zealously protective of his public image. He lived in an era when being outed as gay would cost anyone his career and reputation, and he was not one to risk such consequences.

The story that Hoover, a lifelong bachelor, participated in cross-dressing all-male sex parties in New York hotel rooms, as reported by British writer Anthony Summers in a 1993 biography, has been widely debunked by historians. The story’s source, the wife of a businessman and Hoover confidante, had a grudge from a contested divorce, and other investigations of the story came up empty.

If Hoover did have a gay relationship, most likely it was with his longtime FBI associate director, Clyde Tolson, another lifelong bachelor — but even this is disputed. Hoover and Tolson worked together more than 40 years. They traveled on vacation and official business, rode to work together, shared lunch nearly every day at Washington’s Mayflower hotel and sometimes even wore matching suits. Hoover, at his death, left Tolson most of his estate. Their relationship, by all appearances, was stable, discreet and long-lasting. But what they did physically behind closed doors, if anything, was between them.

2. Hoover’s secret files kept presidents from firing him.

Hoover had particularly good relationships with at least two presidents he served under: Franklin D. Roosevelt and Lyndon Johnson. Of the others, Harry Truman, Dwight D. Eisenhower, John F. Kennedy and Richard Nixon all considered sacking him, but, files aside, they had good political reasons for keeping Hoover. Even in the 1960s, he had a strong public image as an honest, competent law enforcement technocrat. While his relationship with John and Robert Kennedy was often tense — yes, it was Hoover who, through wiretaps of Chicago mob boss Sam Giancana, discovered President Kennedy’s liaison with mob-connected socialite Judith Campbell Exner — Hoover also could have been covering up embarrassing secrets for Camelot.

Still, Hoover built his FBI files into an intimidating weapon, not just for fighting crime but also for bullying government officials and critics and destroying careers. The files covered a dizzying kaleidoscope — Supreme Court justices such as Louis Brandeis and Felix Frankfurter, movie stars Mary Pickford and Marilyn Monroe, first lady Eleanor Roosevelt, physicist Albert Einstein, Zionist leader Chaim Weizmann and philanthropist John D. Rockefeller III, among others — often replete with unconfirmed gossip about private sex lives and radical ties.

3. Hoover was a coward.

Critics often accused Hoover of cowardice, pointing, for instance, to the fact that he didn’t join the military in June 1917, when he finished law school and the country was entering World War I. Instead, he took a draft-exempt job at the Justice Department.

Hoover, by most signs, would have preferred to join his contemporaries going “over there” to fight the Germans. At Central High School in Washington, D.C., he joined the cadet corps and was its captain during his senior year. He relished the pomp and ceremony, marching in uniform and palling around with his fellow cadets.

Rather than fleeing the draft, the more likely reason that Hoover took the Justice Department job in 1917 was that his 61-year-old father, Dickerson Naylor Hoover, who suffered from mental illness, had been forced to leave his job as a government clerk without a pension, making young J. Edgar financially responsible for the family.

4. Hoover was African American.

There are two theories that Hoover had African American heritage. One has it that he was born to an African American mother and secretly adopted by the Hoover family, a theory based on discrepancies in certain birth and census records. However, genealogist George Ott investigated the claim, failed to substantiate it, and said he believes it to be false.

More plausible are stories like that told by writer Millie McGhee in her 2000 book “Secrets Uncovered: J. Edgar Hoover — Passing for White?” McGhee, an African American, claims that, based on family stories and genealogical records, she and Hoover had a common ancestor, a great-grandfather, making him a distant cousin. Hoover’s father’s family had roots in Virginia and Mississippi in the antebellum South, where interracial liaisons were not uncommon. Some mixing in his family tree is a possibility but remains unproven.

5. Hoover’s legacy is a stain on the FBI’s reputation.

Hoover leaves a bipolar legacy. For better or worse, he built the FBI into a modern, national organization stressing professionalism and scientific crime-fighting. For most of his life, Americans considered him a hero. He made the G-Man brand so popular that, at its height, it was harder to become an FBI agent than to be accepted into an Ivy League college.

But he also stands as a reminder that 48 years of power concentrated in one person is a recipe for abuse. It was mostly after his death that Hoover’s dark side became common knowledge — the covert black-bag jobs, the warrantless surveillance of civil rights leaders and Vietnam-era peace activists, the use of secret files to bully government officials, the snooping on movie stars and senators, and the rest.

— Kenneth D. Ackerman, a Washington, D.C. lawyer, is the author of “Young J. Edgar: Hoover and the Red Scare, 1919-1920.”