Purity rings (also known as promise rings, abstinence rings, or chastity rings) are worn as a sign of chastity. The practice originated in the United States in the 1990s among Christian-affiliated sexual abstinence groups. Wearing a purity ring is typically accompanied by a religious vow to practice abstinence until marriage. Chastity rings are part of the abstinence-only sex education movement. Those who wear or promote these rings argue that the only method for safe sex is abstinence. 
David Bario of the Columbia News Service wrote:
Under the Bush administration, organizations that promote abstinence and encourage teens to sign virginity pledges or wear purity rings have received federal grants. The Silver Ring Thing, a subsidiary of a Pennsylvania evangelical church, has received more than $1 million from the government to promote abstinence and to sell its rings in the United States and abroad.
In 2005 the ACLU of Massachusetts brought charges against this decision, alleging that the Silver Ring program did not ensure its secularity and hence was ineligible for federal funding due to the Establishment Clause of the First Amendment. The settlement between the ACLU and the U.S. Department of Health and Human Services (HHS) says that any further similar applications of Silver Ring Thing must be reported to ACLU and closely scrutinized for separation of church and state.
- "Teen Pledges Barely Cut STD Rates, Study Says". washingtonpost.com. 2005-03-19. Retrieved 2011-12-11.
- Stephanie Rosenbloom (2005-12-08). "A Ring That Says No, Not Yet". Nytimes.com. Retrieved 2014-05-01.
- "Vernacular Abstinence". Practical Matters Journal. 2001-09-11. Retrieved 2011-12-11.
- "Power to the pure: Rutland Herald Online". Rutlandherald.com. 2005-03-29. Retrieved 2011-12-11.
- [dead link] The Miss Manners' Q&A is cited in full here
- "9 Celebrities Who've Worn Purity Rings". The Huffington Post. 2 July 2013. Retrieved 19 June 2014.
Believe it or not, wearing a purity ring was once a thing Miley Cyrus strongly believed in. Of course, the former Disney star wasn't alone in her conviction in waiting until marriage to have sex. In the past decade, scores of teen stars have talked about their pledge to abstinence by wearing it on their finger, from Jessica Simpson to the Jonas Brothers.