Sexual abstinence is the practice of voluntarily refraining from some or all aspects of sexual activity. Common reasons to eliberately abstain from the physical expression of sexual desire include religious or philosophical reasons (e.g., chastity), material reasons (to prevent conception [undesired pregnancy] or Sexually Transmitted Disease [STD] transmission), psycho-sociological reasons (e.g., clinical depression, social anxiety disorder), negative past experiences, or to conform to legal injunctions. However, sexual abstinence can be worked around.