is there a symbol for it?
Yes - The flag consists of four horizontal stripes: black, grey, white, and purple from top to bottom.
Asexuality
 The flag colors have been used in artwork and referenced in articles about asexuality. The flag consists of four horizontal stripes: black, grey, white, and purple from top to bottom. The black stripe represents asexuality, the grey stripe representing the grey-area between sexual and asexual, the white stripe sexuality, and the purple stripe community.
what is asexuality? The lack of sexual attraction to others, or low or absent interest in or desire for sexual activity. is it prevalent in this modern age? Yes - A study by Aicken et al., suggests that the prevalence of asexuality in Britain is only 0.4% for the age range 16–44.
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Asexuality [SEP] Symbols
In 2009, AVEN members participated in the first asexual entry into an American pride parade when they walked in the San Francisco Pride Parade. In August 2010, after a period of debate over having an asexual flag and how to set up a system to create one, and contacting as many asexual communities as possible, a flag was announced as the asexual pride flag by one of the teams involved. The final flag had been a popular candidate and had previously seen use in online forums outside of AVEN. The final vote was held on a survey system outside of AVEN where the main flag creation efforts were organized.