(1.) The difficulty of defining sex -offences in a scientifically meaningful manner reflects a more general problem of criminology. Sexual deviations when handled as sex -offences are usually covered by law in sections of the criminal Code entitled Sodomy, Incest, Forcible rape, Carnal abuse and so on. Prostitution and adultery, although sex -offences, are not abnormal sex -offences. The legal definitions are not very accurate descriptions of abnormal sex -offences.
(2.) AGGRESSION and sexuality are fundamental needs of all species where survival depends upon competitive sexual reproduction. The aggressive and sexual expressions of an individual vary in relation to a multitude of factors. Some of the most salient features of which are genetic make up, hormonal and environmental influences at critical periods of development and like experiences in toxication and external events. The causal relations between any of these and the overt behaviour that might be classed as a sex offence under one or another definition are highly complex and only partially understood. Some segments of this multivariate nexus have, however, been subjected to a sufficiently wide variety of observations to allow for broad generalisation.
(3.) THE present century has seen marked changes in public morality; descriptive, analytic and quantitative studies of offences and offencers; two waves of public attention to sex -offences (the first culminating in sexpsychopath legislation, the second in rape law reform and improved victim services); and promising advances in treatment of certain offenders.