Official Scientology views on sex are based on the written works of Church of Scientology founder L. Ron Hubbard. These make up the Standard Tech, or core doctrine, of the Church.

In 1982 Hubbard authored Pain and Sex, a controversial official decree in which the biological act of sex and the body's ability to feel pain were said to be "the invented tools of degradation" created by psychiatrists millions of years ago, noting that "the stocks-in-trade of psychs are pain and sex." This is a key teaching behind Scientology's vehement opposition to all forms of psychiatry, which states that psychiatrists "have been on the track a long time and are the sole cause of decline in this universe." According to Hubbard, "When sex enters the scene, a being fixates and loses power", and "Lovers are very seldom happy."^[1]

In Hubbard's original Dynamics, "Sex" was the Second Dynamic, representing both the sexual act and the family unit. In the Life Orientation Course (written in 1979 before Hubbard's death but published after in 1990), the definition replaced "Sex" with "Creativity". This new definition was later used in compiled materials such as the 1998 Introduction to Scientology Ethics. However, some Scientologists claimed the Church had altered the Dynamics, minimizing the importance of sex: "It also incidentally includes sex as a mechanism to compel future survival".^[2]

The tone scale is a gradient chart that describes rational or pro-survival behavior on an individual. The higher a person is in tone scale the higher is his ability to survive. The tone scale is described in detail in the book “The Science of Survival”. Chapter 18 of this book describes the tone scale as it applies to second dynamic: “At the highest MEST point of the Tone Scale, 4.0, one finds monogamy, constancy, a high enjoyment level and very moral reaction towards sex.”^[3]

Selected citations from the Chart of Human Evaluation:^[3]

In The Creation of Human Ability, Hubbard hailed "compelled admiration" as an important step of progress in "Knowingness", as measured on his "Know to Sex" scale. Hubbard stated:

It can be observed that the eating of living flesh or live cells delivers a kind of admiration to the taste, and it can be observed that under torture, duress of all kinds, the tortured one will suddenly, if degradedly, admire his torturer.

Hubbard then went on to say that sex was an even better "communication system" for the same purposes of forced "admiration", and defined the sex act, consensual or otherwise, as "an interchange of condensed admiration particles".^[4][5]

In 1950 Hubbard published Dianetics: The Modern Science of Mental Health, introducing his "science of the mind," Dianetics. He classified homosexuality as an illness or sexual perversion.^[6]

Hubbard's "tone scale", a means of classifying individuals and human behaviour on a chart running from +40 (the most beneficial) to -40 (the least beneficial). Sexual perversion, a category in which he included homosexuality, was termed "covert hostility" and given a score of 1.1, "the level of the pervert, the hypocrite, the turncoat, ... the subversive." Such people were "skulking coward[s] who yet contain[] enough perfidious energy to strike back, but not enough courage ever to give warning."^[7][8]

Hubbard warned against sexual activity (including masturbation) during pregnancy. He believed it had an adverse and dangerous effect on the unborn child because it can hear, understand and experience everything going on, as well as recording it all as engrams which can haunt the person for the rest of their life. This view is at odds with mainstream science, as Paulette Cooper commented in her book The Scandal of Scientology:

Hubbard's theory never makes it really clear, at least in a manner that would be accepted by most medical doctors, exactly how engrams can be planted before a foetus had developed a nervous system or the sense organs with which to register an impression, or even how a person could retain or 'remember' verbal statements before he had command of a language."^[9]

These same beliefs form the basis for Hubbard's "Silent birth" doctrine, which dictates that no words are spoken during the childbirth process in order to avoid the baby hearing them and recording them as engrams.^[10]

In the 1967 book The Dynamics of Life (originally written circa 1948), Hubbard states that "promiscuity inevitably and invariably indicates a sexual engram of great magnitude. Once that engram is removed, promiscuity can be expected to cease". A footnote then defines promiscuity as "having sexual relations with many people".^[11] Hubbard's book The Way to Happiness includes "Don't be promiscuous" among its twenty-one precepts, right alongside "Do not murder" and "Do not steal". He also blames "sexual promiscuity in monasteries" as the cause of Buddhism's decline in 7th century India.^[12]

In later years, Hubbard sought to distance himself from efforts to regulate the sexual affairs of Scientologists. In a 1967 policy letter, he declared: "It has never been any part of my plans to regulate or to attempt to regulate the private lives of individuals. Whenever this has occurred, it has not resulted in any improved condition... Therefore all former rules, regulations and polices relating to the sexual activities of Scientologists are cancelled."^[13]

In his 2008 book Tom Cruise: An Unauthorized Biography , Andrew Morton writes that Nicole Kidman discussed her sex life with Tom Cruise in Scientology "Auditing" sessions.^[14] Morton writes that details of Kidman's sex life with Cruise was to be leaked by the Church of Scientology if she spoke out critically against the organization after their 10-year relationship that had broke off in 2001.^[14] According to the book Kidman had fears she would be blackmailed.^[15] This was denied by the Scientology head in Australia, Vicki Dunstan.^[14]

In 2007, New Idea reported that Scientology has "sex lessons" which can be given to couples looking to educate themselves to have "better sex".^[16] The couples share intimate details from their sex lives with an adviser referred to as "an intimate relationship guide".^[16] This guide studies their sex life and suggests ways for the couple to improve upon their activities.^[16] The article, titled: "Scientology Sex Scandal", which discussed the relationship of Tom Cruise and Katie Holmes, was one of the more popular articles in Australian publishing in 2007.^[17]

Hubbard called the physical world MEST, which is something ethereal Thetans temporarily operating "meat bodies", are meant to transcend and conquer. Thetans are of the "Theta Universe", and the entire purpose of the Theta Universe is, in Hubbard's words, "the conquest, change, and ordering" of this universe.^[18]

Scientologists often refer to their bodies as "this piece of meat," or "this meat of ours"^[19] and new recruits to the church are classified as "raw meat". ^[20] Scientology is geared towards attaining "cause over MEST", attaining awareness that our bodies are undesirable physical objects that are only holding us back, and attaining the ability to abandon one's body via "exteriorization" and ultimately by becoming an Operating Thetan Clear and a Cleared Theta Clear.^[21] The Scientology Tone scale, in fact, lists needing a body (and all body-related matters) among the lowest of all possible states.

• Homosexuality and Scientology
• Religion and sexuality

Note: HCOB refers to "Hubbard Communications Office Bulletins", HCOPL refers to "Hubbard Communications Office Policy Letters", and SHSBC refers to "Saint Hill Special Briefing Courses". All have been made publicly available by the Church of Scientology in the past, both as individual documents and in bound volumes.