By Joey Bartolomeo
June 29, 2009 12:00 PM

The images are iconic TV moments: Precious little Chastity Bono, with her blonde hair and chubby cheeks, gracing her parents’s 1970s variety show The Sonny and Cher Comedy Hour with a family song or the sweet sign-off, “Goodnight everybody and God bless!” Yet while girls at home may have been envious of Cher’s glittery outfits, Chastity—who always wore costumes to complement Mom and Dad’s—later admitted, “I especially liked it when they put me in clothes that matched my father’s.” In fact, when Chastity came out as a lesbian to The Advocate in 1995, she said, “As a kid I thought I was a little boy.”

It wasn’t just a phase. That towheaded tot turned 40 in March and is now in the process of becoming a man. On June 11 publicist Howard Bragman released a statement announcing that “after many years of consideration,” his client, now called Chaz, “has made the courageous decision to honor his true identity”—that is, to live life as a male. “It is Chaz’s hope that his transition will open the hearts and minds of the public regarding this issue,” continues the statement, “just as his coming out did nearly 20 years ago.” (Transgender people believe they were born as the wrong sex, so except in quotes, PEOPLE will refer to Chaz as “he,” even when referring to past events, to reflect what Bono considers his true gender.)

So far, Chaz’s family are accepting the change—though not without concern. In an exclusive statement to PEOPLE, Cher says, “Chaz is embarking on a difficult journey, but one that I will support. I respect the courage it takes to go through this transition in the glare of public scrutiny, and although I may not understand, I will strive to be understanding. The one thing that will never change is my abiding love for my child.” (The singer, 63, has struggled with Chaz’s choices before: In his book Family Outing, Chaz says Cher kicked him out upon learning he was gay; they quickly reconciled. Recently, they celebrated Chaz’s birthday in Vegas.)

Meanwhile Sonny’s widow, congresswoman Mary Bono Mack, 47, agrees, telling PEOPLE, “Chaz has always been a loving and important part of our family who has supported us all through thick and thin. This is a very difficult decision that Chaz has fully vetted, and over the past decade, [he] has discussed the matter thoroughly and consulted therapists and medical experts. As he moves forward, I will be there to support him and love him every step of the way.” Of course, even for close relatives, learning to think of Chaz as a “he” may take some time. “Whatever way she goes is fine with me,” Cher’s mother, Georgia Holt, told Palm Springs’s Desert Sun. “I love her and I’m behind her.”

Chaz, a former Entertainment Media Director for the Gay and Lesbian Alliance Against Defamation, had been questioning his gender identity for years. According to Michele Kort, who cowrote his 2002 memoir, The End of Innocence, Chaz wondered whether he was a lesbian. “She felt more like a man who loved women instead of like a lesbian,” says Kort.

None of that seems to matter to his girlfriend of a few years, graduate student Jennifer Elia, 33, who is sticking by him through the transition. “Jen is very tolerant and respectful,” says longtime family friend and Bono’s Celebrity Fit Club costar Bruce Vilanch. “I think that they both really felt that they’d found the person they were meant to be with.” Adds a source who knows the couple: “Jennifer is adorable, smart and funny. It takes a really special person who can just fall in love with the person no matter what they do.”

Living openly as a man is part of the transition process, which “brings a person’s body in alignment with their true gender identity,” explains Masen Davis, executive director of San Francisco’s Transgender Law Center. Like most female-to-male transsexuals, Chaz is taking testosterone to alter his body and voice (see sidebar). He also plans to have surgery, which may include a double mastectomy.

Chaz (who had a hysterectomy in 2005 due to endometriosis) yearned for a physical change at least as far back as 2001, says Kort. “She didn’t want to have breasts anymore,” she says. “She wanted to be seen as a man.” Chaz, she adds, was even “fine” about growing facial hair. Kort believes he waited so long to transition because “she was really afraid of embarrassing her mom.” Cher had hoped for a daughter who’d be comfortable in feathers and sequins, not men’s shoes. “I wanted her to be a girlie girl,” Cher has said.

Pressure from Mom didn’t change Chaz’s preference for male attire, whether on Halloween (he liked being Dracula or Wolfman) or playing dress-up. When an 11-year-old Chaz put on a leather jacket and slicked-back pompadour while goofing around, Cher has said, “I was frightened.” On the other hand, Chaz’s childhood bond with his dad was stronger, though they were estranged at the time of Sonny’s death in 1998 because of the late politician’s stance on gay rights. “[My father] really wanted a son,” Chaz has explained, “and I was kind of naturally inclined to that.”

A self-described “punk tomboy,” Chaz privately came out as a teen while studying acting in New York City. Though he enjoyed playing female as well as male characters, he felt limited by his mannish ways. “I felt I always came up short when I played a conventional female part,” he has said, “because my demeanor was too masculine.”

Now he can fully embrace that masculinity—and not just for himself. “The country watched him grow up,” says Shannon Price Minter, the legal director of the National Center for Lesbian Rights, who is transgender. “People already love him. To learn about transgender issues from someone like that is very powerful.” Whether or not Chaz paves the way for social acceptance, friends are already cheering for his new life. “She was uncomfortable having to play a sexual role that was not hers, so this is a gigantic step,” says Vilanch. “I called and said, ‘Go for it!'” Adds Kort: “It will be fantastic.”