Disclaimer: Only adults have sex here. Nothing to get freaked over. This is a semi-serious essay, I hope.
***** WHAT IS INCEST? *****
Do you go to family gatherings
looking for fuck-partners?
MOTHERFUCKER!
Well, that is one way to start.
It is pretty common in Russian to say
"YΓ³b tvoyΓΊ mat"
, meaning "Really?!" or "Gosh!" But literally it is "(I) fucked your mother" and serves as an emphatic exclamation. "What, you can't pay me yet? Fuck your mother!" "Oh no, the team lost again, fuck your mother!" "What a babe, fuck your mother!" "The bus never even slowed down for me, fuck your mother."
This does not go over too well in the Anglophone world.
Who was the first motherfucker? Probably not Oedipus. Human sons (and daughters) have been fucking their parents, and vice-versa, for a long long time. Those kids have been fucking each other too, and uncles, aunts, grandparents, cousins, all one big happy horny family fuckfest, right?
Yeah, lots of Mommy-fucking and Daddy-sucking and sister-swapping, right?
-----
Wait. Let us start over.
Just what the fuck IS incest? Alas, like True Religion, there is no simple answer. The biology is pretty simple but still ambiguous: If you have sex with someone whom you share a certain quantity of DNA, it is genetic incest.
But what is the critical ratio of DNA? And what does "having sex" mean?
DNA first. It's called consanguinity, or "with the blood", even though literal blood has nothing to do with it. The Anglish language is a bit archaic, hey?
Anyway, we measure degrees of consanguinity. (I will omit double-cousins and similar rarities.) Your identical twin or clone has the same DNA as you -- zero degree, no separation. Your parents, children, and full siblings have 1/2 of your DNA -- first degree. Your blood uncles, aunts, grandparents, and grandchildren have 1/4 of your DNA -- second degree. Your blood first cousins have 1/8 of your DNA -- third degree. Other blood cousins have even smaller proportions.
(My partner's parents are second cousins. Their great-grandfather said their kids would be morons with tails. He was wrong. Whew.)
Some say fucking relatives is not incest unless pregnancy is possible, penis in vagina (PIV) -- a strict Bill Clinton definition of "having sex" -- and is discouraged because of possible birth defects. What are those chances?
Fucking your clone or identical twin will not have much effect unless one of you undergoes some serious XY-chromosomal tinkering. Mating with parents, children, or siblings DOES likely have serious birth defect risks -- but good hard data is lacking. Figure a risk between about 10% to 30% above the general population. For first cousins the risk is in the range of 1.5-3%.
Now we hit ambiguity. First-degree fucking is generally verboton. But cousin or uncle-niece mating is common or even expected in much of the world -- in some places, up to 60% of all marriages! Genetic incest in one place is not considered such elsewhere. Some cultures ban sex within the clan or moiety where any shared DNA is vanishingly small; other cultures insist on it.
Do you prefer a culture where you cannot marry your cousin or uncle, or one where you must, or one where you have an option?
Family can have a lot of sweaty fun if only PIV baby-making sex is 'incest'. Stick with oral or manual gratification; squirt the semen soup into a mouth or anus or armpit or empty eye socket. First base, second base, third base -- safe!
-----
So much for biology. Humans DO occasionally think with brains instead of gonads; we social animals have developed rules, mores, taboos. And laws. Laws up the wazoo. Some are even reasonable. But nowhere are they consistent.
Many jurisdictions outlaw sex with in-laws as incest. With certain in-laws, anyway. And with step-relatives. These fuckers may have essentially zero shared DNA but they're still 'family'. And even ex-in-laws and ex-step-kin are considered family in some places.
This makes much real-world sense. IRL (In Real Life) incest is usually abusive, usually an older male victimizing a child. A step-parent or father-in-law or uncle by marriage may have been a notable authority figure in a child's life; the fucking is compelled, not consensual, whether or not the younger person is of age. Is it incest even if they are not blood kin?
Such "authority figures" may not even be family, but if they are close -- teachers, pastors, counselors, godparents -- they are just as sexually abusive. Rape is rape, whether inflicted by papa or padre or pedagogue.
And I label such authority-figure abuse as just that, abuse.
But I can't see all in-law or step-kin sex as incest. Suppose old Dad has rid himself of old Mom by divorce or death and marries a Sweet Young Thing not much older than studly 19-year-old Sonny. Sweetie is now legally Sonny's step-mother -- as of the marriage last month. Is she an authority figure? Is their fucking incest or merely unsurprising cheating?
My story APPLES & ORANGES (to be finished and posted Real Soon Now) is about a divorced father of four marrying a widowed mother of three and merging their families into one big house. Most of the kids are aged 18-19 and have a good time exploring the sexuality of their new step-kin. It posts in Group Sex, not Incest. They have not been 'family' long enough to cross that line. I do not know how laws handle this.
-----
Once again, what is incest?
I know very well what Incest is here on LITerotica. It is the most popular category. It is what most of you pervs (er, I mean Gentle Readers) hunger for. Oh Daddy! Oh Mommy! Yes, THAT is what you guys and gals want.
The most-read stories numbers do not lie. Most of you desire hot-n-heavy motherfucking, followed by hard-driving fatherfucking, then steamy-sweet sister-brother action. Intertwined sisters are down the list. Cousin and in-law sex do better than uncle or aunt sex. Brothers 69ing do not rate well.
LIT Incest is not IRL incest. IRL incest is grubby; consensual adult incest is vanishingly rare. LIT Incest is sanitized, often moving, more often just stroking. The Incest stories I write are for your fantasies, not mine.