An ancient Indian text about love that has been popularized in modern times for its creative and spiritual sexual content, including a variety of intercourse positions. Contrary to popular belief, the Kama Sutra is not historically connected to the practice of tantra.

A model of the human sexual response developed in the 1970s by noted sex therapist, Helen Singer Kaplan, including: the sexual desire phase, the excitement phase and the resolution phase. Kaplan built on the work of Masters and Johnson, adding desire to their model of the human sexual response cycle. Later, another sex researcher, Rosemary Basson, proposed that for women desire may come after arousal.

(1929-1995) A pioneer in the field of sex therapy. She received her Ph.D. in psychology and in the early 1970’s founded the Human Sexuality Program at the Payne Whitney Clinic, part of the New York Hospital-Cornell Medical Center. She wrote many publications including “New Sex Therapy: Active Treatment of Sexual Dysfunctions," “Disorders of Sexual Desires and Other New Concepts and Techniques in Sex Therapy," “The Illustrated Manual of Sex Therapy," and "Sexual Aversion, Sexual Phobias and Panic Disorder." She is also known for developing the triphasic model of sexual response—desire, excitement and orgasm.

A type of cancer that causes lesions under the skin and in a variety of organs including the lining of the mouth, nose and throat. It is often associated with AIDS, as an opportunistic infection. Lesions are generally red or purple in color.

A device designed to be inserted into the vagina to improve the effectiveness of Kegel exercises. A Kegel exerciser is usually shaped like a slim dildo, often with areas of thickness intended to tighten and train the vaginal muscles around.

Two groundbreaking reports published by sex researcher, Dr. Alfred Kinsey of the Institute for Sex Research at Indiana University (later re-named as The Kinsey Institute for Research in Sex, Gender and Reproduction). Sexual Behavior in the Human Male was published in 1948 and Sexual Behavior in the Human Female was published in 1953. Both were based on Kinsey's interviews with thousands of men and women, systematically studying and documenting for the first time the incidence of such taboo topics as homosexuality, premarital sex, oral sex and masturbation.

In 1948, Alfred Kinsey, Wardell Pomeroy and Clyde Martin developed a continuum that explained their research findings on sexual orientation. A tool for self-evaluation, the scale ranges from 0 to 6—highlights include 0 being exclusively heterosexual, 3 being equally heterosexual and homosexual and 6 being exclusively homosexual.

(1894-1956) A pioneering American researcher in human sexuality, who wrote The Kinsey Reports. The groundbreaking reports were based on Kinsey's interviews with thousands of men and women, documenting for the first time the incidence of such taboo topics as homosexuality, premarital sex, oral sex and masturbation. Kinsey was trained as a biologist and zoologist, recognized for his research on the gall wasp, but he spent most of professional life studying human sexuality. Today, Kinsey remains a controversial figure because of his research methods, but he is credited with bringing sexuality into the public awareness and considered a forefather of the sexual revolution.

Touching and caressing with the lips. Kissing is a common part of sex play in many cultures, and some forms of kissing are an expression of affection among family members, friends or acquaintances. Many styles of kissing exist, including friendly kisses, deep kisses and kissing parts of the body. Kissing plays an important role in emotional intimacy.

A condition in which a boy is born with an extra X chromosome. Klinefelter syndrome is linked to problems with language and social development as infants, and more feminine characteristics and infertility after puberty due to low testosterone and sperm production.