The Only Unnatural Sex Act Is That Which One Cannot Perform

Alfred Kinsey? Richard Brinsley Sheridan? Xaviera Hollander? William Burroughs? Sigmund Freud? Anonymous?

Dear Quote Investigator: Years ago I read a statement credited to the researcher Alfred Kinsey who was famous for producing the Kinsey Reports on sexual behavior. I do not remember the exact phrasing but the expression was similar to this:

The only unnatural act is one you cannot perform.

Kinsey’s book “Sexual Behavior in the Human Male” was released in 1948, and “Sexual Behavior in the Human Female” was published in 1953. Both of these books were very controversial when they were published. I looked through them but was unable to find the quotation. Could you explore this saying?

Quote Investigator:  A precursor to this statement appeared in a satirical comedy by the prominent Irish playwright and poet Richard Brinsley Sheridan in 1779. “The Critic: or, A Tragedy Rehearsed” was first performed in London, and it included the following line in Act 2, Scene 1:

Certainly nothing is unnatural that is not physically impossible.

This statement appeared within the comedy when a character named Puff was explaining the plot of another play which contained a love match between two characters of different nationalities: 1 2

SNEER. No scandal about Queen Elizabeth, I hope?
PUFF. O Lud! no, no.—I only suppose the Governor of Tilbury Fort’s daughter to be in love with the son of the Spanish admiral.
SNEER. Oh, is that all?
DANGLE. Excellent, Efaith!—I see it at once.—But won’t this appear rather improbable?
PUFF. To be sure it will—but what the plague! a play is not to shew occurrences that happen every day, but things just so strange, that tho’ they never did, they might happen.
SNEER. Certainly nothing is unnatural, that is not physically impossible.

QI has not yet located the statement in a work written by Alfred Kinsey. The earliest evidence known to QI of a close match appeared in 1963 in an article in the Mattachine Review by Harold L. Call who was President of the Mattachine Society. The words were credited to Alfred Kinsey: 3

I suggest that the varied forms of sexual behavior are simply a part of nature. I urge others to regard them so. I remember Dr. Kinsey once said that the only unnatural sex act is that which one cannot perform. Then let’s start accepting the fact, and chuck into the rubbish can a lot of the prudish nonsense the anti-sexualists are feeding us.

Here are additional selected citations in chronological order.

In 1966 the saying was printed in an essay in Time magazine where the words were attributed to Kinsey: 4

Homophile opinion rejects the notion that homosexuals are sick, and argues that they simply have different tastes. Kinsey had a lot to do with this, for to him all sexual pleasure was equally valid. “The only unnatural sex act,” he said, “is that which you cannot perform.”

In 1967 the quote was published in the New York Times and Kinsey was credited: 5

But no public utterance from a position of disinterested authority has yet told Americans what they should think or do about homosexuality. Alfred Kinsey’s assurance that “the only unnatural sex act is that which you cannot perform” was a conundrum of semantics.

In 1979 the statement was included in “The Book of Quotes” compiled by Barbara Rowes: 6

The only unnatural sex act is that which you cannot perform.
— Alfred Kinsey

In 1987 the “Barnes & Noble Book of Quotations” edited by Robert I. Fitzhenry presented a variant expression ascribed to Sigmund Freud. QI has not yet attempted to trace this variant quote: 7

The only unnatural sexual behaviour is none at all.               Freud

In 2005 a version of the saying was connected to the author Xaviera Hollander: 8

“The only unnatural act is one which cannot be performed” was the signature email sign-off from Xaviera Hollander, the former Happy Hooker, sexuality educator, Penthouse columnist, and advocate for sexual rights.

A blog entry dated 2005 presented a collection of sayings that had been transcribed from buttons. The collection included a version of the saying with an attribution to William Burroughs: 9

“The only unnatural act is the one which cannot be performed.” William Burroughs

In conclusion, a precursor of the quotation was contained in a 1779 play by Richard Brinsley Sheridan. The first close match known to QI was ascribed to Albert Kinsey in 1963. But QI has not yet located any direct evidence that the quote was written or spoken by Kinsey who died in 1956. It does seem to be compatible with Kinsey’s viewpoint. There were minor variations in the wording, e.g., “one cannot perform” was printed in 1963 and “you cannot perform” was printed in 1966.

(Thanks to the anonymous person who sent an inquiry and gave impetus to this exploration.)


  1. 1781, “The Critic Or a Tragedy Rehearsed: A Dramatic Piece in Three Acts as it is performed at the Theatre Royal in Drury Lane” by Richard Brinsley Sheridan, Quote Page 49, Printed for T. Becket, London. (Google Books full view) link
  2. Oxford Reference Online, Quick Reference: The Critic by Richard Brinsley Sheridan, Information from The Oxford Dictionary of Plays, Entry: The Critic, Oxford University Press. (Accessed on March 20, 2013)
  3. 1963 August, Mattachine Review, Volume 9, Number 8, The Hypocrisy of Sexual Morality by Harold L. Call, Start Page 4, Quote Page 12, Published by the Mattachine Society, San Francisco, California. (Reprint edition from Arno Press, New York, 1975) (Verified with scans; thanks to Stephen Goranson and Duke University library system)
  4. 1966 January 21, Time, Essay: The Homosexual in America, Time, Inc., New York. (Time magazine Online Archive)
  5. 1967 November 12, New York Times,  Civil Rights and the Homosexual: A 4-Million Minority Asks for Equal Rights by Webster Schott, Start Page 44 (ProQuest Page 271), Quote Page 62, New York. (ProQuest)
  6. 1979, The Book of Quotes, Compiled by Barbara Rowes, Quote Page 199, A Sunrise Book: E. P. Dutton, New York. (Verified on paper)
  7. 1987, Barnes & Noble Book of Quotations: Revised and Enlarged, Edited by Robert I. Fitzhenry, Section: Sex, Quote Page 327, Barnes & Noble Books, Division of Harper & Row, New York. (Verified on paper)
  8. 2005 copyright, The Art of Sex Coaching: Expanding Your Practice by Patti Britton, Quote Page 26, W. W. Norton & Company, New York. (Google Books Preview)
  9. Website name “Not Quite an Army of Monkeys Typing”, Blog entry title: Portable Philosophy, Date of blog entry: November 30, 2005, Handle of blog author: Eric the Something of Phoenix Arizona, Twitter handle: Eric Fiallos. (Dates on websites may be inaccurate) (Accessed on March 20 2013) link