Sexology - is the systematic study of human sexuality in all of it's manifestations. It encompasses all aspects of sexuality, including attempting to characterize "normal sexuality" and its variants, including femdom and female domination.
Modern sexology is a fascinating field which uses the techniques of fields including fetish, fantasies, psychology, role reversal, domination, submission, sociology, anthropology, and sometimes deviant behavior to bear on its subject. It studies human sexual development from childhood and the development of sexual relationships as well as the mechanics of sexual intercourse and sexual malfunction. It also documents the sexuality of special groups, such as submissive men, dominant women, and sadistic women, and studies sexual deviance such as sex addiction and forms of sexual abuse.
Note that sexology is considered multi faceted, not just reproductive in nature: it attempts to document reality, not to prescribe what behavior is suitable, ethical, or moral. Sexology has often been the subject of controversy between supporters of sexology, those who believe that sexology pries into matters held sacrosanct, and those who philosophically object to its claims of objectivity and empiricism. It studies the roots of male masochism and female sadism and what causes these bizarre forms of behavior. Sexology is an emerging subject that is drawing a lot of attention since it's emergence in the second half of the twentieth century.
One of the earliest sex researchers prior to the 20th century sexology movement was Richard Freiherr von Krafft-Ebing, whose book Psychopathia Sexualis, published in 1886, recorded a dizzying array of sexual anomalies. Early in the 20th century, Sigmund Freud developed a theory of sexuality based on his studies of his clients. Wilhelm Reich and Otto Gross, were disciples of Freud, but rejected by him because of their emphasis of the role of sexuality for the revolutionary struggle for the emancipation of mankind. None of them could possibly imagine how complex sexual manifestations could become as human population expanded and the natural course of sexual behavior became increasingly complex. Sex for reproduction purposes only, survival of the species, etc., began a sharp decline during this century. Fantasy sex during this time had a sharp increase in popularity and de emphasized reproductive motivations.
Additional Resources
Bitch Island - Beautifully illustrated website with in depth descriptions of the female domination fantasy