look. i came into this respectfully disagreeing with you, but then i looked into it myself, and i do have to say: i agree, mostly. this is one of the few times i will talk about sexual topics on my page because this one's unavoidable it's inherently going to be brought back to sex sorry. i also mention sexual violence, csa and sexual assault in this, so be wary.
first off, i acknowledge that you have fair points, quite a few actually. first of all, the concept of incest is very much more heavily demonized than it really needs to be. i would like to assume this is not only due to the stigma around it being a paraphilia but also because of history showing the effects of long-term inbreeding, and how it caused intense health risks for individuals. i agree that there are likely many circumstances where the same family dynamic does not apply to individuals who would be blood relatives, such as for example cousins who see themselves more as friends like you said. i would also like to add the fact that some forms of incest are not directly genetically harmful, such as a pair of adopted siblings, something i cannot remember if you mentioned.
i do agree that it is definitely a strange double standard for incestuous relationships to be criminalized due to the reason of "a possibility child comes out disabled." i would like to add the fact that it also paves the way for someone with very bad-faith intentions to attempt to, as you alluded to, criminalize disabled people having children as well.
in doing my own reading on this, i found a quote by martin o'reilly, stating, "indeed, it’s worth noting that with respect to huntington’s disease — a distressing, impairing brain disorder — if one parent has it, there’s a 50 percent chance any child he/she has will also be born with the fatal disorder. But if we don’t punish those carrying defective genes from having children, why then should we punish incestuous partners? if we’re not prepared to prevent carriers of congenital disorders from having children —or, for that matter, having sex — then it seems quite arbitrary and discriminatory to only punish incestuous partners." i think it's a pretty well-stated commentary on this phenomenon and the double-standard enforced here. i'm not going to make commentary on the ethics of attempting to stop anyone from having children who are disabled or who may be disabled, simply because it is a highly complex issue that i am not one side on. i can recognize points on both sides that are well spoken, and i can see people on both sides having genuinely good-faith opinions on the matter.
however, i would not use the word eugenics here. i feel as if that may be too heavy a word to be using in this situation, as eugenics has been used as part of a collection of ideologies used to systemically discriminate against and even genocide individuals before, which i would not like to compare the act of incest to. i feel as if that waters down the suffering victims of eugenics have gone through.
my original arguments were for the unhealthy power dynamic between individuals who have grown up as family members, but... there is no evidence i can find of that power dynamic other than in fringe situations. i have only seen criticism of your reference of "destroying a family dynamic" or "emotional harm to the other family members," and commentary proving the exact opposite, or commentary on incestuous abuse, or incest not practiced by two consenting adults (see: child abuse). in fact, in the abstract of a book i found legitimately criticizing incest as it would harm the family dynamic, the author directly states "that being said, i argue that there is insufficient legal justification for all consensual, adult incest to be criminalised. i examine four potential arguments in favour of consensual, adult incest being illegal, and conclude that none of them succeeds in justifying a total legal prohibition against it."
turning back to martin, who puts it in a way that really puts it into perspective for me, specifically when he talks about an explanation by vera bergelson, detailing "the legal scholar vera bergelson points out this argument is both overbroad and redundant. it’s overbroad in the sense that it applies to cases where power dynamics, abuse, or exploitation do not exist. (speaking of which, we don’t prohibit nonincestuous adult relationships merely because one partner is older, richer, or has more social status than the other). the argument is also redundant as there are already statutes directed at child abuse and statutory rape, as well as sexual exploitation or violence (irrespective of the age of the victim). the sexual acts between relations here would be immoral not because they are incestuous, but because they would amount to rape, violence or exploitation; we already regard such behaviour as wrong, independent of whether or not incest occurred." honestly if i could quote his entire breakdown of it, i would. i'll try not to, though.
while i would love to treat this going into this with the passion of a thousand suns throwing out proof that it's actually really terrible and you are So Stupid To Believe That.... well, first of all, this was something written in complete good faith with cited scholarly sources and second of all i don't do that usually lol. and third of all... there really is no evidence! i would love if someone could pop into this and give some articles that disprove op and i's statements in defense of consensual incest, i've found that every article i've seen talking about it in a negative light have been
only speaking of incest between father and daughter, especially in cases of csa. paints all father-daughter relationships as the father directly asserting dominance over the daughter (which in most cases may be the case) and paints any other situations, like mother-son incest, as either the woman being the victim (denying the concept that women can be aggressors and/or rapists and that men can be victims of rape) or somehow the son is the problem.
treating sibling incest as somehow the fault of the father for not being "dominant enough" in the family, therefore causing the brother to be the source of power. repeat the earlier statements about father-daughter relationships.
ignoring the concept of incestuous relationships between, say, cousins, or aunt and nephew.
for these, i would check out this article which in the preview breaks down parts of weinberg's incest behavior. additionally, if you feel privy, feel free to do as i did and browse google scholar attempting to find one link to an abstract or synopsis that isn't in defense of consensual adult incest. seriously, it's more difficult than you would think.
i... have had every argument i had dismantled, honestly. i had one about the increased amount of inbreeding that would come from the decriminalization and normalization of incest, but guess what: good old martin coming back again. "this might be a fair objection if there was good reason to assume the decriminalisation of adult incest would lead to a significant rise of inbreeding. but as we know, there are already a small number of countries that currently don’t ban adult incest, and we’ve no reason to believe there are significant instances of inbreeding in those countries. there’s also evidence to suggest the practice will never become widespread: various studies have shown that people who live together in close proximity during early life become desensitised to future sexual attraction."
....so, yeah. op, you're right on this one! seriously, i invite anyone to try and disprove this in a way that a. cites evidence that is either as reputable as or more reputable than ours (hey, i'd take anything above a blog post lol), b. doesn't use "it's gross" as a reason, and c. doesn't inherently dismiss the concept that women can be aggressors or perpetuates the concept that all family dynamics have to be the Nuclear Family, Actually. hell, i'm lenient on that last one, that's an opinion you can have, even if i personally don't agree with it.
also, just to recap op's first commentary: this is not on the topic of sexual abuse. this is not attempting to erase the effect on incest on sexual abuse, or how victims of incest especially as children may experience large amounts of trauma relative to that. abuse is fucked up and bad, that isn't a hot take or anything. i recognize that abuse, especially sexual violence, especially sexual violence against a family member is really fucking bad. that being said, this is specifically referring to cases of consensual incestuous relationships between adults.
i have a couple more points (effect of incest on abusive relationships and how that may make it harder to escape them but how that is the fault of the abuse and not an inherent fault of incest and how there's tons of societal complications in all different power dynamics that also make it harder to escape but those aren't criminalized yadda yadda my thoughts are all over the place here bear with me) but i'm gonna leave it there. don't worry no-more-rqs i'm getting sent to superhell for my terrible incest defending right here with you. lol