The Rainbow (or Gay Pride) Flag was created by artist and vexillographer (fancy ass name for flag- designer) Gilbert Baker, a friend of the late Harvey Milk, who was an American politician who was the first openly gay man to be elected to public office in California, as a member of the San Francisco Board of Supervisors. He was assassinated in November 1978-the same year the flag began to be used prominently in San Fransisco. Baker, dyed and sewed the first flag himself. The flag debuted at the San Francisco Gay and Lesbian Freedom Day Parade. It has since been used around the world as a symbol of LGBT unity in many variations, including adaptations such as bumper stickers and decals. The Rainbow Flag is frequently credited as being recognized by the International Congress of Flag Makers (ICoFM). There is no such thing as the ICoFM but was actually a slip of the tongue in an interview where baker confused the organization FIAV (English version of FIAV, or the International Association of Vexillological Associations) and the event Flag Congress.
Changes made to the flag:
There is much debate as to how the flag went from 8 to 7 to 6 and some accounts state that it went strait from 8 to 6. Here are a number of the theories:
1. The pink stripe was drooped because Baker ran out of pink Dye
2. San Francisco-based Paramount Flag Co. began selling seven-striped (top to bottom: red, orange, yellow, green, blue, indigo, and violet) flags from its Polk Street retail store, which was located in a large gay neighborhood. These flags were surplus stock which had originally been made for the the International Order of Rainbow for Girls, a Masonic organization for young women. As these were so readily available, they for a time became the 'gay pride' flag out of convenience.
Baker goes commercial...
3. Apparently after the pink was dropped by Baker and his volunteers, Baker desired an even number of stripes on the flag.
Baker asked Paramount to make vertical banners that would be split and displayed from the angular double bars of the old-style lamp posts on Market Street. Baker and Paramount’s vice president Ken Hughes agreed to drop the hot pink and turquoise stripes and replace the indigo stripe with royal blue — resulting in three stripes on one side of the lamp post and three on the other.
The reality was that the gay community at this time (1978-1979) used almost any flag with a rainbow of stripes. Here are some examples of other rainbow flags...
Italian peace flag, same design as the Greek peace flag which reads "epihnh" -peace in Greek (http://en.wikipedia.org/wiki/Peace_symbol#The_Peace_Rainbow_Flag)
Jewish autonomous oblast in Russia (http://en.wikipedia.org/wiki/Jewish_Autonomous_Oblast)
Meher Baba -Indian spirituality