Gregory Hemingway, son of Ernest and recently a woman

Gregory Hemingway, the youngest son of novelist Ernest Hemingway and a former physician who underwent a late-in-life sex-change operation, died Monday in a private cell in the Miami-Dade Women's Detention Center in Florida.

He was 69.

Miami-Dade police said an autopsy revealed that Mr. Hemingway, who suffered hypertension and cardiovascular disease, died of natural causes.

A spokeswoman for the Miami-Dade County Corrections and Rehabilitation Department said medical staff confirmed that Mr. Hemingway had undergone a sex- change operation and was classified as a female when he was booked into the women's detention center.

Mr. Hemingway was arrested on Key Biscayne, an island community near Miami, five days before his death. Responding to a park ranger's report of a naked pedestrian, police charged Mr. Hemingway with indecent exposure and resisting arrest without violence.

Police said Mr. Hemingway, who was found holding a dress and high heels, appeared to be drunk or otherwise impaired during the arrest.

Mr. Hemingway's death marked the end of a tormented life, one that included,

by his own admission, drink, depression, nervous breakdowns, electroshock treatments and a desire to wear women's clothes.

The son of the great novelist and his second wife, Pauline Pfeiffer, Gregory Hemingway was born in 1931 in Kansas City, Mo. He spent his early years in Key West, Fla.

In his 1976 best-selling book "Papa: A Personal Memoir," the novelist's son portrayed his father as a loving childhood companion who taught him to be a champion wing shot and once displayed his courage by rescuing his young son from sharks.

But Mr. Hemingway clearly had mixed feelings about his father, with whom he had an increasingly strained relationship in later years.

In his book, he said his father blamed him for his mother Pauline's death in 1951. She died only hours after having a heated long-distance phone call with her ex-husband in Cuba over Gregory's use of a mind-stimulating drug while visiting the West Coast.

Years later Mr. Hemingway discovered that his mother had a rare adrenal gland disorder and that the emotionally charged phone call had likely produced an abnormally high surge of adrenaline that caused her blood pressure to rise to the point of rupturing an artery.

"After that episode with mother (on the phone), I simply wanted to kill him, " Gregory Hemingway told a reporter more than two decades later. "I hated his guts for years. But I came to understand him."

Despite the earlier good times with his father, Gregory Hemingway had a troubled childhood, according to author Jeffrey Meyers in "Hemingway: A Biography." In 1941, Ernest Hemingway told Pauline that their 10-year-old son had "the biggest dark side in the family except me."

In his early 20s, Gregory Hemingway followed in his father's footsteps by going on safari to Africa, where he shot 18 elephants in one month. Living on an inheritance from his mother, he worked three years as an apprentice hunter. But his uncontrollable drinking, he later wrote, prevented him from obtaining a professional hunter's license.

In his memoir, Mr. Hemingway said he became a physician after apparently allaying the impulse to become "a Hemingway hero."

By the early '70s, he was working as an industrial physician in New York City, a job he described as "necessary but dull."

He said he wrote the memoir of his father to make enough money to flee Manhattan and start a new life.

He chose the wide open spaces of Montana -- Hemingway country -- and in 1976 took up residence in Fort Benton on the Missouri River, where he went to work in a storefront medical clinic .

Mr. Hemingway was married four times and had eight children.