Individuals make a choice to seek gratification of the biological need for companionship according to their most complete arousal level, and their own built-in erotic programming, their eroticization, their individual erotic awakening. In order to best understand orientation, we must recognize that there are individuals called fetishist, who have orientations for objects, the practice of which is called a fetish. These individuals have a maximum arousal and a fantasy threshold for shoes, rubber, latex, clothing, and other objects which are not per se sexual at all, except by association in the minds of the afflicted individual. This is the result of an erotic awakening at some inopportune moment. There is such a strong psychological link to the pleasure center in the mind of the fetishist that the sufferer frequently finds no substitute for the maximum arousal which the practice of that fetish gives the sufferer.
Heterosexuality means having a maximum arousal level based upon opposite gender stimuli.
The study of preference includes an examination of homosexuality, which is only one of several broad categories, including bestiality and pedophila, which refer to choosing of partners for sexual gratification. An affliction known as homoeroticism is necessarily the underlying cause of true homosexuality. Homoeroticism means having a fantasy arousal level for same sex scenarios. A male has to break that link and seek a new female to fixate upon. However the female has to flip and reverse fixation from the female to the male, and then she must select a mate.