A bit of internet research also found this:
"New York may have more gay residents. Montreal may have a larger gay village. But San Francisco is the undisputed gay capital of the world. How did it get such a status? Perhaps it’s the location, snug on a peninsula in the middle of a breathtaking bay surrounded by majestic hills. Perhaps it’s the famous attractions, like the Golden Gate Bridge, Alcatraz, Fisherman’s Wharf, with its wax museum, and Pier 39, with its sea lion community and Ripley’s Believe it or Not. Perhaps it’s the recreation areas that abound in the city, like Golden Gate National Recreation Area, a wild, untamed chunk of land on the bay perfect for hiking and kayaking, and Golden Gate Park a swathe of green larger than New York’s Central Park, filled with walking paths, museums, and performance spaces. Perhaps it is the unique neighborhoods, like Chinatown, largest of its kind in North America, Union Square, with its shopping, The Haight, with its punks, goths, and hippies, The Mission, with its nightlife and strong Latino heritage, Nob Hill, with its funky shops and great dining, SoMA, with museums and galleries, and the legendary Castro, the heart of Gay America. It could be any of these things, but we think the reas"on SF is the gay capitol of the world goes back much farther…all the way back to the era when it was called “Sodom by the Sea.” The 1800s. When rich gold miners indulged in every vice imaginable. This started the precedent for gay residence in the area. And in the 1970s when the police informed the residents of San Francisco and the world that as many as 70,000 gay residents might be living in the city, the city didn’t care, and the oppressed gay residents of the world responded by moving to San Fran to be among their own kind.
And today it is estimated that nearly a third of the city’s residents are gay, and no city in the world is more influenced by its queer citizens. The city’s gay community tends to be politically charged, but laid-back, stressing individuality rather than fashion and beauty. Though The Castro is the famous gay center, you’ll find gay establishments and residences spread out liberally across all the neighborhoods of San Francisco (with noticeable collections in Hayes Valley and SoMa.) BART, the Bay Area Rapid Transit, is one of the nation’s best, and alleviates the need for a car in this congested city.
San Francisco hosts one of the largest Pride events on the planet. Normally the last week in June, the event draws tens of thousands of revelers and activists, and is equal parts politics and party. In mid-June, Frameline, the International Lesbian and Gay Film Festival, is held. It’s the oldest and largest homo-film festival in the world. Up Your Alley is a major leather event held in Dore Alley. It takes place at the beginning of August (or end of July), and is second in popularity only to the Folsom Street Fair in late September, the defining event of the San Francisco leather community. In early October, the Castro Street Fair closes the street with dancing and entertainment. The AIDS Candlelight Memorial and Mobilization is a global event on the last Sunday of May. It had its beginnings here in San Francisco in 1983."http://www.edirp.com/gay-travel-guides/gay-san-francisco-guide.php