Despite female sadists being less visible than males, some surveys have resulted in comparable amounts of sadistic fantasies between females and males. The results of such studies indicate that ones sex may not be the determining factor for a preference towards sadism. Medical and forensic classification
Medical categorization
BDSM
Medical opinion of sadomasochistic activities has changed over time. The classification of sadism and masochism in the Diagnostic and Statistical Manual of Mental Disorders (DSM) has always been separate; sadism was included in the DSM-I in 1952, while masochism was added in the DSM-II in 1968. Contemporary psychology continues to identify sadism and masochism separately, and categorizes them as either practised as a life style, or as a medical condition.The current version of the American Psychiatric Associations manual, DSM-5, excludes consensual BDSM from diagnosis as a disorder when the sexual interests cause no harm or distress. Sexual sadism disorder however, listed within the DSM-5, is where arousal patterns involving consenting and non‐consenting others are not distinguished

ICD
On 18 June 2018, the WHO (World Health Organization) published ICD-11, and Sadomasochism, together with Fetishism and Transvestic Fetishism, are now removed as psychiatric diagnoses.
In other words, the sadomasochist generally desires that the pain be inflicted or received in love, not in abuse, for the pleasure of either one or both participants. This mutual pleasure may even be essential for the satisfaction of those involved. Here, Ellis touches upon the often paradoxical nature of widely reported consensual S&M practices. It is described as not simply pain to initiate pleasure, but violence—"or the simulation of involuntary violent acts"—said to express love. This irony is highly evident in the observation by many, that not only are popularly practiced sadomasochistic activities usually performed at the express request of the masochist, but that it is often the designated masochist who may direct such activities, through subtle emotional cues perceived or mutually understood and consensually recognized by the designated sadistIn his essay Coldness and Cruelty, (originally Présentation de Sacher-Masoch, 1967) Gilles Deleuze rejects the term "sadomasochism" as artificial, especially in the context of the quintessentially modern masochistic work, Sacher-Masochs Venus In Furs. Deleuzes counterargument is that the tendency toward masochism is based on intensified desire brought on or enhanced by the acting out of frustration at the delay of gratification. Taken to its extreme, an intolerably indefinite delay is rewarded by punitive perpetual delay, manifested as unwavering coldness. The masochist derives pleasure from, as Deleuze puts it, the "Contract": the process by which he can control another individual and turn the individual into someone cold and callous. The sadist, in contrast, derives pleasure from the "Law": the unavoidable power that places one person below another.