# Did you ever have sex with a sibling? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [November 24, 2003, 2:10am UTC](https://boards.straightdope.com/t/did-you-ever-have-sex-with-a-sibling/214920 "2003-11-24T02:10:01Z")\ **Posts on this page:** 20\ **Page:** 6
**Author:** ![look\_hergo](https://avatars.discourse-cdn.com/v4/letter/l/85e7bf/32.png) [@look\_hergo](https://boards.straightdope.com/u/look_hergo)\ **Post date:** [December 3, 2003, 9:40pm UTC](https://boards.straightdope.com/t/did-you-ever-have-sex-with-a-sibling/214920/101 "2003-12-03T21:40:16Z")
I have two male friends who have both told me that while growing up, they played sex games with their brothers. Hand jobs, blow jobs, etc. “J” insists that all brothers do this sort of thing. “D” and his brother used the name “Jabberjaw” for their game. They both seem pretty nonchalant about it. Of course, this IS the pacific NW… ---
**Author:** ![AngelicGemma](https://avatars.discourse-cdn.com/v4/letter/a/439d5e/32.png) [@AngelicGemma](https://boards.straightdope.com/u/AngelicGemma)\ **Post date:** [December 3, 2003, 10:36pm UTC](https://boards.straightdope.com/t/did-you-ever-have-sex-with-a-sibling/214920/102 "2003-12-03T22:36:42Z")
> [@](#): > > \*Originally posted by Flamsterette\_X \* > \*\*Worldwide, about 20% of all married couples are first cousins. > \*\* cite? ---
**Author:** ![Ranchoth](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ranchoth/32/1066_2.png) [@Ranchoth](https://boards.straightdope.com/u/Ranchoth)\ **Post date:** [December 4, 2003, 7:52am UTC](https://boards.straightdope.com/t/did-you-ever-have-sex-with-a-sibling/214920/103 "2003-12-04T07:52:06Z")
Uncle John’s Unstoppable Bathroom Reader, page 55, if I’m not mistaken. ---
**Author:** ![Moirai](https://avatars.discourse-cdn.com/v4/letter/m/96bed5/32.png) [@Moirai](https://boards.straightdope.com/u/Moirai)\ **Post date:** [December 4, 2003, 9:41pm UTC](https://boards.straightdope.com/t/did-you-ever-have-sex-with-a-sibling/214920/104 "2003-12-04T21:41:53Z")
Like **shrew** said above, my brother is a great guy. Smart, funny, good looking, an absolute catch. If he weren’t my brother, I’d marry him in a New York Minute. But he is, so I won’t. And IIRC, what was mentioned above is correct- incest does not automatically doom offspring to hideous birth defects, or even increase the risks substantially. In my long-ago anthro courses, it was indicated that incest needed to continue for several generations before latent genetic problems began to occur. I could be wrong, but I will look for a cite in the meantime. ---
**Author:** ![Moirai](https://avatars.discourse-cdn.com/v4/letter/m/96bed5/32.png) [@Moirai](https://boards.straightdope.com/u/Moirai)\ **Post date:** [December 4, 2003, 9:47pm UTC](https://boards.straightdope.com/t/did-you-ever-have-sex-with-a-sibling/214920/105 "2003-12-04T21:47:17Z")
**"Another theory is that the observance of the taboo would lower the incidence of congenital birth-defects caused by inbreeding. Anthropologists reject this explanation for two reasons. First, inbreeding does not lead to congenital birth-defects per se; it leads to an increase in the frequency of homozygotes. A homozygote encoding a congenital birth-defect will produce children with birth-defects, but homozygotes that do not encode for congenital birth-defects will decrease the number of carriers in a population. If children born with birth-defects die (or are killed) before they reproduce, the ultimate effect of inbreeding will be to decrease the frequency of defective genes in the population…"** From [http://en.wikipedia.org/wiki/Incest\_taboo](http://en.wikipedia.org/wiki/Incest_taboo) ---
**Author:** ![Moirai](https://avatars.discourse-cdn.com/v4/letter/m/96bed5/32.png) [@Moirai](https://boards.straightdope.com/u/Moirai)\ **Post date:** [December 4, 2003, 9:52pm UTC](https://boards.straightdope.com/t/did-you-ever-have-sex-with-a-sibling/214920/106 "2003-12-04T21:52:36Z")
And here- **"According to the recent report, children of unrelated parents have a 3 percent to 4 percent chance of being born with a serious birth defect. Children of first cousins have only a slighter higher risk–roughly a 4 percent to 7 percent chance. Thus, the ban on cousin marriages will not go very far toward the general problem of preventing birth defects."** From here, an interesting article about incest taboos and the law- [http://us.cnn.com/2002/LAW/04/columns/fl.grossman.incest.04.09/](http://us.cnn.com/2002/LAW/04/columns/fl.grossman.incest.04.09/) ---
**Author:** ![aahala](https://avatars.discourse-cdn.com/v4/letter/a/a88e4f/32.png) [@aahala](https://boards.straightdope.com/u/aahala)\ **Post date:** [December 5, 2003, 2:11am UTC](https://boards.straightdope.com/t/did-you-ever-have-sex-with-a-sibling/214920/107 "2003-12-05T02:11:55Z")
Does this count? I had sex with my mother’s only child. ---
**Author:** ![Flamsterette\_X](https://avatars.discourse-cdn.com/v4/letter/f/41988e/32.png) [@Flamsterette\_X](https://boards.straightdope.com/u/Flamsterette_X)\ **Post date:** [December 5, 2003, 3:10am UTC](https://boards.straightdope.com/t/did-you-ever-have-sex-with-a-sibling/214920/108 "2003-12-05T03:10:25Z")
> [@](#): > > \*Originally posted by Ranchoth \* > \*\*Uncle John’s Unstoppable Bathroom Reader, page 55, if I’m not mistaken. \*\* I don’t remember the page number, and I can’t check since I’m not home. [Here’s another cite.](http://listarchives.his.com/smartmarriages/smartmarriages.0204/msg00009.html) F\_X ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [December 5, 2003, 5:58am UTC](https://boards.straightdope.com/t/did-you-ever-have-sex-with-a-sibling/214920/109 "2003-12-05T05:58:58Z")
[Sequential thread alert] the thread right below this one is entittled “Anyone ever been involved in Big Brothers / Big Sisters” 😃 Carry on [/STA] ---
**Author:** ![Silver\_Serpentine](https://avatars.discourse-cdn.com/v4/letter/s/3be4f8/32.png) [@Silver\_Serpentine](https://boards.straightdope.com/u/Silver_Serpentine)\ **Post date:** [December 5, 2003, 11:24am UTC](https://boards.straightdope.com/t/did-you-ever-have-sex-with-a-sibling/214920/110 "2003-12-05T11:24:54Z")
Well, my great-grandparents were first cousins, and I have no more defects than anyone else I know (ADD, Depression, Bad Eyesight, Premature Atrial Contractions). Like a few others on here have said, as long as they’re consenting adults . . . No problem here. One of my friends was completely against it. For being such a liberal on everything else (aside from breat feeding her child - because she had one friend that had an orgasm while bfing her children), she believes one must be completely mentally ill to harbor any feelings toward ones blood relatives. Eh. Inbreeding can cause problems, eventually. I have an example of such (not human, but my area of expertise isn’t really humans). Burmese Pythons. When they first came out for public buying in, oh, the 80’s, everyone wanted Albinos. Albino’s were worth a boatload of money, so much inbreeding was done - someone would buy one albino, have one litter with a normal, which would result in a batch of simple recessive. Once one of the SRs was old enough to mate, it’d be bred back to its parent, resulting in about 50% albino. For 100% albino, they’d breed said babies together or with the grandparent. This was the cheap way to do things, instead of just buying 2+albinos to start with, even if it took longer. This has happened to a leser extent with the other morphs - green, labryinth, etc. ANYWAY, this resulted in what we in the snakie biz call Burm’s Disease (those of us who believe in it - and anyone who knows anyone who does Burm rescue does). What happens is, after about the age of 4 (a year after breeding age, so a BD carrier can breed and have babies sold without knowing they’re a carrier), if the snake catches a respiratory infection, it’s immuse system is weakened to RIs for the rest of its life. Like a reverse vaccine. Most Burms with BD are luckly to live to the age of 8 before it drowns in its own phlegm. BUT it only becomes weakened by RIs (which is the most common ailment for most snakes, anyway). Now, if a snake with BD is kept in good enough condition that it never gets that initial RI, it can keep breeding about every other year in females (every year is possible, but it’s really hard on females to have a litter every year), or multiple times a year if male. So, te gene gets spread even wider. But that was _generations_ of inbreeding - remember, a Burm can breed atround age 3. It’s been 20ish years. Many generations. OR if you want a human example, just do a search for the Blue Fugates. Interesting stuff, that is. But I, personally, have never seen any problems arise from, say, brother/sister or mother/son inbreeding in rats. In a litter of 10 with an albino mother, I usually only get 2 albino babies. Even if the dad was het for albino. And albino seems like a pretty strong recessive trait. Sorry. I get kind of long winded when I actually have knowledge on a subject, heh. ---
**Author:** ![Silver\_Serpentine](https://avatars.discourse-cdn.com/v4/letter/s/3be4f8/32.png) [@Silver\_Serpentine](https://boards.straightdope.com/u/Silver_Serpentine)\ **Post date:** [December 5, 2003, 11:29am UTC](https://boards.straightdope.com/t/did-you-ever-have-sex-with-a-sibling/214920/111 "2003-12-05T11:29:32Z")
Ahem. They would have a batch of 100% heterozygous (het) babies. Not simple recessive. Geh. Substitute het for Simple recessive in places. Too bad I can’t edit my own posts. ---
**Author:** ![AngelicGemma](https://avatars.discourse-cdn.com/v4/letter/a/439d5e/32.png) [@AngelicGemma](https://boards.straightdope.com/u/AngelicGemma)\ **Post date:** [December 5, 2003, 3:11pm UTC](https://boards.straightdope.com/t/did-you-ever-have-sex-with-a-sibling/214920/112 "2003-12-05T15:11:42Z")
> [@](#): > > \*Originally posted by AnimistDragon \* > \*\*she had one friend that had an orgasm while bfing her children), \*\* WHAT?! Ew!!! ---
**Author:** ![Swampwolf](https://avatars.discourse-cdn.com/v4/letter/s/8edcca/32.png) [@Swampwolf](https://boards.straightdope.com/u/Swampwolf)\ **Post date:** [December 5, 2003, 4:44pm UTC](https://boards.straightdope.com/t/did-you-ever-have-sex-with-a-sibling/214920/113 "2003-12-05T16:44:31Z")
so…if you have sex with your _clone,_ would that me homosexuality, incest, or just masturbation? ---
**Author:** ![Swampwolf](https://avatars.discourse-cdn.com/v4/letter/s/8edcca/32.png) [@Swampwolf](https://boards.straightdope.com/u/Swampwolf)\ **Post date:** [December 5, 2003, 4:48pm UTC](https://boards.straightdope.com/t/did-you-ever-have-sex-with-a-sibling/214920/114 "2003-12-05T16:48:32Z")
damn. **be,** of course. ---
**Author:** ![Surreal](https://avatars.discourse-cdn.com/v4/letter/s/eada6e/32.png) [@Surreal](https://boards.straightdope.com/u/Surreal)\ **Post date:** [December 5, 2003, 4:54pm UTC](https://boards.straightdope.com/t/did-you-ever-have-sex-with-a-sibling/214920/115 "2003-12-05T16:54:26Z")
Why does this thread have **6500** views? Apparently a lot of Dopers are sib-curious. ---
**Author:** ![jjimm](https://avatars.discourse-cdn.com/v4/letter/j/ba8739/32.png) [@jjimm](https://boards.straightdope.com/u/jjimm)\ **Post date:** [December 5, 2003, 4:57pm UTC](https://boards.straightdope.com/t/did-you-ever-have-sex-with-a-sibling/214920/116 "2003-12-05T16:57:53Z")
Back in the 17th century in my family tree, one of my great-greats married his brother’s daughter. Anyway, this thread reminds me of one of the sickest jokes I know. Dare me to post it? ---
**Author:** ![Shodan](https://avatars.discourse-cdn.com/v4/letter/s/9f8e36/32.png) [@Shodan](https://boards.straightdope.com/u/Shodan)\ **Post date:** [December 5, 2003, 6:34pm UTC](https://boards.straightdope.com/t/did-you-ever-have-sex-with-a-sibling/214920/117 "2003-12-05T18:34:56Z")
> [@](#): > > How Many Spasms Do You have During Orgam? Hahahahahahaha! Freudian typo! Everybody knows it’s spelled _origami_. Regards, Shodan ---
**Author:** ![Loneraven](https://avatars.discourse-cdn.com/v4/letter/l/c0e974/32.png) [@Loneraven](https://boards.straightdope.com/u/Loneraven)\ **Post date:** [December 5, 2003, 9:24pm UTC](https://boards.straightdope.com/t/did-you-ever-have-sex-with-a-sibling/214920/118 "2003-12-05T21:24:46Z")
> [@](#): > > \*Originally posted by jjimm \* > \*\*Back in the 17th century in my family tree, one of my great-greats married his brother’s daughter. > > Anyway, this thread reminds me of one of the sickest jokes I know. > > Dare me to post it? \*\* Dare ya, **jjimm**. ---
**Author:** ![sugaree](https://avatars.discourse-cdn.com/v4/letter/s/cc9497/32.png) [@sugaree](https://boards.straightdope.com/u/sugaree)\ **Post date:** [December 5, 2003, 9:59pm UTC](https://boards.straightdope.com/t/did-you-ever-have-sex-with-a-sibling/214920/119 "2003-12-05T21:59:37Z")
Double-dare ya. ---
**Author:** ![Olentzero](https://avatars.discourse-cdn.com/v4/letter/o/90ced4/32.png) [@Olentzero](https://boards.straightdope.com/u/Olentzero)\ **Post date:** [December 5, 2003, 10:20pm UTC](https://boards.straightdope.com/t/did-you-ever-have-sex-with-a-sibling/214920/120 "2003-12-05T22:20:55Z")
Triple-_dog_ dare ya. [Previous page](https://boards.straightdope.com/t/did-you-ever-have-sex-with-a-sibling/214920.md?page=5) [Next page](https://boards.straightdope.com/t/did-you-ever-have-sex-with-a-sibling/214920.md?page=7)