Asexuality (or nonsexuality) is the lack of sexual attraction to anyone, or low or absent interest in sexual activity. It may be considered the lack of a sexual orientation, or one of the variations thereof, alongside heterosexuality, homosexuality and bisexuality. It may also be an umbrella term used to categorize a broader spectrum of various asexual sub-identities. A study in 2004 placed the prevalence of asexuality at 1% in the British population.