Some psychological theories view perversion as a split between "genital sexuality" (as a loving force) and "pregenital" impulses, often rooted in early trauma or a mortal terror of intimate, reciprocal relationships. 2. Clinical and Legal Evolution

Historically, perversion was defined as any sexual activity that "distorts, blocks, or interferes with" what a society or theory deems to be normal sexual development.

Traditional views often labeled acts as perverse if they strayed from the "natural" biological purpose of procreation.

The classification of these behaviors has shifted from moral or religious "sins" to medical and psychological conditions. 2 Perversions in Men and Women - PEP-Web

Philosophers like Thomas Nagel argue that for a practice to be called a perversion, it must be viewed as an unnatural sexual inclination.