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Who really said it

The Only Unnatural Sex Act Is That Which One Cannot Perform

Attributed to Alfred Kinsey 1894–1956 · American sexologist and biologist
Attributed Rights unconfirmed

Widely credited to Kinsey and consistent with the argument his books actually made — but no book, paper, lecture text or recording of his has ever been shown to contain the sentence. The earliest known printing is an August 1963 magazine article in which another man recalls hearing Kinsey say it, seven years after Kinsey’s death, and Quote Investigator has found no direct evidence he wrote or spoke it ↗.

Last verified 8 Sep 2026 · how we verify · spot an error?

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Unconfirmed quote & credit

“The Only Unnatural Sex Act Is That Which One Cannot Perform” Attributed to Alfred Kinsey (1894–1956), but unsourced: it has never been located in any work written by Kinsey. Earliest known printing is Harold L. Call, "The Hypocrisy of Sexual Morality," Mattachine Review, August 1963, p. 12 — a recollection published seven years after Kinsey's death. Via Quotle.info.

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We couldn’t establish where this was first published, so there’s no rights status to give. Credit it as shown above — just don’t present it as public domain, and get permission for commercial or published reuse.

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In context

Evoking the world of Alfred Kinsey — American sexologist and biologist · founded the Institute for Sex Research, 1947. Theme: "The Only Unnatural Sex Act Is That Which One Cannot Perform". Atmospheric and restrained, cinematic directional light, a muted period-appropriate palette, fine grain and texture. Compose with generous empty space for the quote and a small credit line. No lettering in the image itself.

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Provenance

The earliest paper trail

Earliest known printing
Mattachine Review, vol. 9, no. 8 (August 1963)
Reported by
Harold L. “Hal” Call, president of the Mattachine Society, in “The Hypocrisy of Sexual Morality” (p. 12)
In Kinsey’s own books
Not found — neither Sexual Behavior in the Human Male (1948) nor Sexual Behavior in the Human Female (1953)
Status
Attributed posthumously; no manuscript, transcript or recording located

I remember Dr. Kinsey once said that the only unnatural sex act is that which one cannot perform. Recollection, August 1963

These are Call’s words, not Kinsey’s: a recollection of something he says he heard, printed seven years after Kinsey died in 1956. Quote Investigator verified the passage against scans of the August 1963 issue — which establishes that Call wrote it, not that Kinsey said it.

Magazine essay
Time, “Essay: The Homosexual in America,” 21 January 1966
Quote Investigator’s full citation chronology, 1779 to 2005

How we verified this

  • 1779 — a precursor, not a source. In Sheridan’s The Critic ↗, Sneer answers an objection about an implausible plot: “Certainly nothing is unnatural, that is not physically impossible.” The same logical move, a different subject.
  • August 1963 — the first close match. Harold L. Call, president of the Mattachine Society, writes in the Mattachine Review that he remembers Kinsey saying it. Quote Investigator verified the page against library scans ↗. Kinsey had been dead since 1956.
  • 21 January 1966 — it reaches the mass market. An unsigned Time essay ↗ quotes it as Kinsey’s, in the reworded form “that which you cannot perform.” The New York Times repeats the attribution in November 1967, and quotation dictionaries pick it up from 1979.
  • 2009 to today — still unsourced. Wikiquote listed the line among Kinsey quotes awaiting a reliable source ↗; another line on that list has since been sourced to his 1953 report and promoted. This one has not.

The sentence has never been tied to a work by Kinsey, so there is no publication date on which a copyright status could turn — we assert none. The earliest documented printing is Call’s August 1963 article in the Mattachine Review, a 1931-or-later publication, so nothing here supports treating the wording as public domain.

Rights status is our research, not legal advice — and copyright varies by country and edition. For commercial or published use, confirm with the rightsholder. See terms.

Fact-check

Who else it gets hung on

No rival originator has been established, but the sentence has been loose enough for decades to pick up other famous names — and to change wording as it travels. The three modern credits below are all later than the Kinsey attribution, and none is sourced to a text either — the fourth entry is an earlier echo, not a rival origin.

Sigmund Freud Variant

A shortened variant was ascribed to Freud in the 1987 Barnes & Noble Book of Quotations ↗. Quote Investigator has not traced that variant to Freud either.

Xaviera Hollander Sign-off, not source

A 2005 book records the line as Hollander’s email sign–off ↗ — using a saying already forty years in print, not coining it.

William Burroughs Button slogan

A 2005 blog collection of slogans transcribed from badges credited this wording to Burroughs ↗, with no work cited.

Richard Brinsley Sheridan Precursor, not source

Sneer says this in Act II of The Critic (1779) ↗ — but he is talking about implausible plots on stage, not sex. It is the same logical move in a different argument, and there is no evidence of a chain connecting it to the modern line.

What is actually established: the sentence is first recorded in print in August 1963, seven years after Kinsey’s death, as one man’s recollection of hearing him say it — and no work written or spoken by Kinsey has been found to contain it ↗.

Context

Why this one stuck

The line works because it performs a magic trick in eleven words: it takes “unnatural,” a moral word, and redefines it as a physical one. Anything a body can do is natural by definition, so the category empties itself. That is very close to the argument Kinsey’s reports were understood to be making — which is precisely why almost nobody stopped to ask whether he said it.

Its documented career runs through respectable rooms fast. It appears in a movement magazine in August 1963, then in an unsigned Time essay of 21 January 1966 ↗ that used it to sum up Kinsey’s position, and by November 1967 in the New York Times, where Webster Schott called the assurance “a conundrum of semantics” ↗. Three citations in four years, and not one of them points to anything Kinsey published.

Every printed record of Kinsey saying this postdates his death.

The wording drift, and the other names it has been hung on

The exact form on this page — that which one cannot perform — is the 1963 wording. The version that went mainstream swaps in the second person: that which you cannot perform, which is what Time printed in 1966 and what quote sites reproduce today. Quote Investigator notes the variation explicitly; neither form has been tied to a text by Kinsey.

Loose lines drift to other famous names, and this one has drifted a lot. A shortened variant has been ascribed to Sigmund Freud, used as an email sign–off by Xaviera Hollander, and printed on buttons under William Burroughs’s name. None of those trails leads anywhere earlier than the Kinsey attribution.

Explore

Filed under

More provenance-checked quotes on the same theme, each with its reuse status.

Freedom Truth

Go further

Dig deeper

Trusted places to keep pulling the thread — primary archives, fact-checks, and scholarship. We show how we used each one before you leave.

Quote Investigator: The Only Unnatural Sex Act Is That Which One Cannot Performquoteinvestigator.com

The anchor investigation: full citation chronology from Sheridan’s 1779 precursor through the 1963 Mattachine Review first match, and the finding that no direct evidence ties the line to Kinsey.
Time, “Essay: The Homosexual in America,” 21 January 1966time.com

The unsigned Time essay that put the saying into wide circulation, quoting it as Kinsey’s in the ‘you cannot perform’ form.
Talk:Alfred Kinsey — Wikiquoteen.wikiquote.org

The quote has sat on Wikiquote’s unsourced list since 2009 and has never been promoted to the sourced article, unlike a neighbouring Kinsey line that was sourced to the 1953 report in 2021.
Alfred Kinsey — Wikiquote (sourced quotations)en.wikiquote.org

Kinsey’s sourced quotations, drawn from the 1948 and 1953 reports and a 1958 volume. This sentence is not among them.
Sheridan, A Trip to Scarborough; and, The Criticgutenberg.org

Full text of the 1779 comedy containing the precursor line Sneer speaks in Act II: nothing is unnatural that is not physically impossible.
Alfred Kinsey — Wikipediaen.wikipedia.org

Biography, life dates (23 June 1894 – 25 August 1956), and the publication history of the Kinsey Reports.

About the man it is pinned on

Alfred Kinsey

Alfred Kinsey

1894–1956 · American sexologist and biologist · founded the Institute for Sex Research, 1947

Alfred Kinsey was an American sexologist, biologist and professor of entomology and zoology who founded the Institute for Sex Research at Indiana University in 1947 — today the Kinsey Institute. He is best known for Sexual Behavior in the Human Male (1948) and Sexual Behavior in the Human Female (1953), the two volumes known as the Kinsey Reports, which made him a household name and a lightning rod. The line on this page fits the reputation those books built for him, which is very likely why it stuck to him — but it has never been found in them.

For writers & researchers

Cite this

Earliest documented attribution

Harold L. Call, “The Hypocrisy of Sexual Morality,” Mattachine Review 9, no. 8 (August 1963): 4, 12 — the earliest close match known to Quote Investigator, credited to Kinsey but not traced to any work of his.

This verification page

Quotle.info. “Who really said ‘The Only Unnatural Sex Act Is That Which One Cannot Perform’?” Last verified 8 Sep 2026. https://quotle.info/who-said/the-only-unnatural-sex-act-is-that-which-one-cannot-perform/

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