Long time before Boy George appeared and became famous, David Bowie already appeared and became famous. Both were born in England. But not like Boy George who always appears feminine, David Bowie experienced development in hair, makeup and dress style.
In certain decades ( maybe between 1970's and 1980's ), Bowie ever appeared in androgynous hair, makeup and dress that made him like a woman. But after that decades, his makeup, hair and dress style changed and he didn't appear in androgynous style again.
His androgynous appearance began in the glam rock era, when he appeared with alter ego Ziggy Stardust. "Ziggy Stardust" itself was a title of his song. I don't know which one was the origin. His song "Ziggy Stardust" that inspired him to be androgynous or his alter ego Ziggy Stardust that inspired him to write a song with the same title "Ziggy Stardust".
Glam rock is a branch of rock music that highlight the glamorous of appearance. Appearance could mean hair, makeup, dress and accessories. To appear glamour, highlighted and sensational is easier if we choose our opposite gender appearance as our appearance.
His another song "John, I'm Only Dancing" can be interpreted as his attitude as a bisexual. Especially with his voice in this song where he used falsetto voice. Like the lyrics "Well, Annie's pretty neat, she always eats her meat. Joe is awful strong, bet your life he's putting us on. Oh lordy, oh lordy, you know I need some loving. I'm moving, touch me!"
"Rebel rebel" is also his song that described the confusion of a mother to her child about its gender. Like in the lyrics "You've got your mother in a whirl. She's not sure if you're a boy or a girl". In that era, rock music seems to inspire a revolution and rebellion in almost all fields of life. It was so extreme until some people said that rock was a music of satan.
