NEW YORK - In the 1970s, Bruce Jenner was a symbol of American masculinity as an Olympic champion. Nearly 40 years later, in an extraordinary television interview, Jenner told the world that he identifies as a woman and has felt gender confusion since he was a little boy growing up in the New York suburbs.

Jenner let his hair down - literally loosening a ponytail and letting his hair flow past his shoulders - in a symbolic moment at the start of his two-hour interview with ABC News' Diane Sawyer that was televised Friday. "Yes, for all intents and purposes, I am a woman."

For the transgender community, it was a moment as significant as Ellen DeGeneres' coming out as a lesbian was for gays nearly 20 years ago. DeGeneres tweeted support to Jenner, saying the former Olympian was "saving lives and opening minds."

"My whole life has been getting me ready for this," said Jenner, 65, known to a younger generation as the patriarch of television's omnipresent Kardashian clan. "It's not just the last few years as they've been treating me as a joke."

The interview was filmed in February in Los Angeles and New York, before a fatal car accident in which Jenner was involved. The Nielsen company said an audience of just fewer than 17 million people saw the interview.

Jenner said he self-identifies as "her," not a specific name. But he told Sawyer he felt comfortable using the pronouns "he" and "him," a designation that is an important issue for many in the transgender community, which believes that transgender people should be referred to by the pronouns with which they choose to identify.

Jenner said his "brain is more female than it is male." He said he began gender reassignment therapy in the 1980s - taking hormones, having surgery to make his nose smaller and having hair removed from his face and chest - but gave it up. As Jenner got older, he realized that if he got sick and faced death without facing up to this issue, "I'd be so mad that I didn't explore that side of my life."

As a young boy, Jenner felt an urge to try on his mother's and sister's dresses.

"I didn't know why I was doing it," he said. "It just made me feel good."

Jenner said he has never been sexually attracted to men, and he wanted to make clear to viewers that gender identity and sexuality were separate things.

"I am not gay," he said. "I am, as far as I know, heterosexual. I've always been with a woman, raising kids."

Jenner said he has not decided whether he will undergo sexual reassignment surgery.

"These are all things that are out there in the future for me to explore," he said. "There's no rush for that. And I would do it so quietly that nobody in the world would know."

Jenner's four oldest children appeared on the interview special to support their father, but not the two girls he had with Kris Kardashian. He said his stepdaughter Kim has been a big supporter, urged on by husband Kanye West, but that his stepdaughter Khloe was taking it the hardest.

Jenner's first two wives offered messages of support; ABC said Kris Kardashian's publicist called to specifically say his third wife would have no comment. But Kardashian tweeted that no one had asked for comment and, after the interview aired, tweeted: "Not only was I able to call him my husband for 25 years and father of my children, I am now able to call him my hero."

Jenner told Sawyer that Kris was having a difficult time with it, and that if she better understood it, the couple would probably still be together.

Jenner's 89-year-old mother also was interviewed, saying she was more proud of Bruce than when he stood as an Olympic champion in Montreal.

The E! Entertainment network announced that Jenner would be part of a documentary series about the transition that would begin airing on July 26.

Hollywood offered support. "Tonight" host Jimmy Fallon, echoing Neil Armstrong when the astronaut took his first steps on the moon, tweeted: "One small step for man, one giant leap for mankind."

"Today, millions of people learned that someone they know is transgender," said GLAAD President & CEO Sarah Kate Ellis. "By sharing this story, Bruce Jenner has shined a light on what it means to be transgender and live authentically in the face of unimaginable public scrutiny. Though Jenner's journey is one that is deeply personal, it is also one that will impact and inspire countless people around the world."

Jenner showed Sawyer a closet filled with dresses and men's clothes. Sawyer said she had a private dinner with Jenner where he wore a dress, but the former Olympian did not appear in one in the ABC special.

Jenner said his two youngest daughters, suspecting that each other was secretly using her clothes, set up a computer to catch the other in the act - only to find their father using their full-length mirror wearing one of his own dresses.

"I would like to think that we can save some lives here," said Jenner, who admitted he once considered suicide at a low point when seen by paparazzi heading to a surgery to have his Adam's apple shaved back. "I have a feeling this is my cause in life. This is why God put me on this Earth, to deal with this issue."