>>24630 by "hardwired" I mean they're part of your brain and pretty much impossible to change. The reason there are "new" kinks these days is because there is new stuff; however, people are still people, so their brains randomly fixate on stuff when they're really little, while their pyschological "love maps" are developing. Scat fetishes are often a sign of difficult toilet training or a childhood illness at a crucial moment, but can also be a sensory crossed wire, because the anus and genitals are really close together, the anus is a very sensitive area, and in addition males are prone to having their prostates stimulated while defecating, especially when constipated. (Scat + similar are probably very common fetishes; they are thought of as niche or extreme because people are generally ashamed of them and unwilling to talk about it.) But while fetishes are definitely formed in early childhood, sexuality is often latent before puberty, so a child with a developing fetish usually experiences mental satisfaction from the fetish object but little to no physical arousal.

For example, I have definitely been fascinated by epidemic scenarios, diseases, and diarrhea since at least age 4 or 5 (that's just how far back I can remember), probably due to a nasty stomach bug that disrupted my toilet training when I was 2 (which I can't remember, but my mom says it happened), but I did not experience genital arousal from it until about age 11. Then, while fantasizing about expelling diarrhea, I noticed (with some annoyance!) that I "felt" the "imaginary" sensation "in the wrong spot." I did not know much about sex and did not know how to masturbate, so I assumed I had just confused the sensations of shitting and peeing. I learned how to masturbate several months later, and while pretty much anything remotely sexual will get a 12-year-old off, the most pleasurable were scat scenarios, or even lists of words for diarrhea or digestive illnesses. Having absolutely no idea what pornography was beyond "pictures of bad things on the internet," I'd read the encyclopedia articles for cholera or dysentary while masturbating. I did not even know what fetishes were until about a year later, when I found a medical encyclopedia–lots of excitingly nasty diseases, and a full-page cross-section of heterosexual "coitus"–which had entries like "paraphilia" and "coprophilia," which, btw, was also the first time anything had told me I should be ashamed of any of this. (Before, I was worried about going to hell, but just for masturbation, not what I was masturbating to.) The full manifestation of my fetish did coincide with puberty but predated full orientation-based sexuality; while I'd had kiddie crushes since I was maybe 9, my first overt sexual attraction to another person was age 14, nearly two years after I started masturbating to scat scenarios.

tl;dr, a real fetish is a permanent fixation formed at an early age that causes involuntary dopamine and other neurochemical release in response to fetish triggers, leading to mental satisfaction or fascination and, except sometimes in children, involuntary sexual arousal. Unless the fetish object is a type of person, the presence of the fetish commonly supersedes sexual orientation or other limits of attraction–for example, a heterosexual man will often be aroused by fetish content even if it contains a male subject, or someone with absolutely no pedophilic tendencies may masturbate to fetish content with loli or shotacon, despite being unaffected or even repulsed by it in other contexts. In some cases, it may be difficult or impossible for a fetish-haver to become aroused without fetish material or fantasies, which may cause personal difficulties, but often fetish-havers can still experience arousal from "normal" sexual situations and do not experience sexual dysfunction in the absence of the fetish.

(tbc, apparently it was too long)