# What do you call this familial relationship? **URL:** \ **Category:** Factual Questions\ **Created:** [March 24, 2022, 8:28pm UTC](https://boards.straightdope.com/t/what-do-you-call-this-familial-relationship/961655 "2022-03-24T20:28:58Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Max\_S](https://avatars.discourse-cdn.com/v4/letter/m/46a35a/32.png) [@Max\_S](https://boards.straightdope.com/u/Max_S)\ **Post date:** [March 24, 2022, 9:11pm UTC](https://boards.straightdope.com/t/what-do-you-call-this-familial-relationship/961655/21 "2022-03-24T21:11:29Z")
Exactly, they may even grow up just as brothers since Thomas’s mom died. If there’s no second family to turn to, there’s not much reason to make the distinction in everyday speech. ~Max ---
**Author:** ![UltraVires](https://avatars.discourse-cdn.com/v4/letter/u/ecccb3/32.png) [@UltraVires](https://boards.straightdope.com/u/UltraVires)\ **Post date:** [March 24, 2022, 9:12pm UTC](https://boards.straightdope.com/t/what-do-you-call-this-familial-relationship/961655/22 "2022-03-24T21:12:41Z")
> [@RitterSport](#): > > Unless the father and sister immediately become estranged, they will grow up just like brothers, not like cousins, so I would say (again) that they are half-brothers. > [@Max\_S](#): > > Exactly, they may even grow up just as brothers since Thomas’s mom died. But your biological relationship doesn’t change because of your parents’ romantic or cohabiting status. ---
**Author:** ![Max\_S](https://avatars.discourse-cdn.com/v4/letter/m/46a35a/32.png) [@Max\_S](https://boards.straightdope.com/u/Max_S)\ **Post date:** [March 24, 2022, 9:13pm UTC](https://boards.straightdope.com/t/what-do-you-call-this-familial-relationship/961655/23 "2022-03-24T21:13:16Z")
Brotherhood has nothing to do with biology. ~Max ---
**Author:** ![UltraVires](https://avatars.discourse-cdn.com/v4/letter/u/ecccb3/32.png) [@UltraVires](https://boards.straightdope.com/u/UltraVires)\ **Post date:** [March 24, 2022, 9:14pm UTC](https://boards.straightdope.com/t/what-do-you-call-this-familial-relationship/961655/24 "2022-03-24T21:14:42Z")
Surely you realize I’m not talking about a membership in the Elks Club. I am talking about what a certain familial relationship is called. Is the GQ answer: “There is no such term”? ---
**Author:** ![Max\_S](https://avatars.discourse-cdn.com/v4/letter/m/46a35a/32.png) [@Max\_S](https://boards.straightdope.com/u/Max_S)\ **Post date:** [March 24, 2022, 9:16pm UTC](https://boards.straightdope.com/t/what-do-you-call-this-familial-relationship/961655/25 "2022-03-24T21:16:11Z")
I’d stick with this > [@Max\_S](#): > > Thomas would be both Patrick’s half-brother and first cousin. > [@UltraVires](#): > > Isn’t this sort of an “a greater subsumes the lesser” status? > [@RitterSport](#): > > Unless the father and sister immediately become estranged, _they will grow up just **like** brothers_, not like cousins, so I would say (again) that **they are half-brothers**. ~Max ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [March 24, 2022, 9:16pm UTC](https://boards.straightdope.com/t/what-do-you-call-this-familial-relationship/961655/26 "2022-03-24T21:16:21Z")
> [@Max\_S](#): > > Brotherhood has nothing to do with biology. My brother, sister and I were adopted so zero biological connection. But, we only ever think of each other as brothers and sister (as does everyone else we know). Biology can certainly denote a relationship but so can how you are raised. ---
**Author:** ![UltraVires](https://avatars.discourse-cdn.com/v4/letter/u/ecccb3/32.png) [@UltraVires](https://boards.straightdope.com/u/UltraVires)\ **Post date:** [March 24, 2022, 9:18pm UTC](https://boards.straightdope.com/t/what-do-you-call-this-familial-relationship/961655/27 "2022-03-24T21:18:33Z")
I certainly approve of adoption and believe that those relationships are on par with biological ones. However, can we not fight what I am driving towards here? ---
**Author:** ![Horatius](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/horatius/32/3572_2.png) [@Horatius](https://boards.straightdope.com/u/Horatius)\ **Post date:** [March 24, 2022, 9:36pm UTC](https://boards.straightdope.com/t/what-do-you-call-this-familial-relationship/961655/28 "2022-03-24T21:36:13Z")
> [@UltraVires](#): > > “First cousins” doesn’t do it justice; they are closer than that. They are also closer than half brothers. First-Half BroCousins of the Weirdest Origin. “Weirdos” for short, because that’s what all the other kids are going to call them anyways. ---
**Author:** ![Horatius](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/horatius/32/3572_2.png) [@Horatius](https://boards.straightdope.com/u/Horatius)\ **Post date:** [March 24, 2022, 9:40pm UTC](https://boards.straightdope.com/t/what-do-you-call-this-familial-relationship/961655/29 "2022-03-24T21:40:22Z")
> [@UltraVires](#): > > Is the GQ answer: “There is no such term”? Being serious, the answer is obviously “Yes”. Why would we have a name for a relationship that almost never happens? ---
**Author:** ![doreen](https://avatars.discourse-cdn.com/v4/letter/d/858c86/32.png) [@doreen](https://boards.straightdope.com/u/doreen)\ **Post date:** [March 24, 2022, 9:44pm UTC](https://boards.straightdope.com/t/what-do-you-call-this-familial-relationship/961655/30 "2022-03-24T21:44:46Z")
Yeah, I don’t think there is a special term. Someone mentioned double cousins earlier- that’s the only “special” term I know of and in my experience , it’s typically used to explain why these cousins are particularly close. There’s at least one bunch in my family - their fathers were brothers and their mothers were sisters. Nobody said “Rose is both Vera’s sister and sister-in-law” or “Uncle Tony is my double uncle because he’s both my father’s brother and my mother’s sister’s husband” or had any special words for these people who filled two slots on the family tree. ---
**Author:** ![Moriarty](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/moriarty/32/49_2.png) [@Moriarty](https://boards.straightdope.com/u/Moriarty)\ **Post date:** [March 24, 2022, 9:49pm UTC](https://boards.straightdope.com/t/what-do-you-call-this-familial-relationship/961655/31 "2022-03-24T21:49:23Z")
Perhaps double cousins would fit. > **[Double first cousin](https://familypedia.fandom.com/wiki/Double_first_cousin)** > > Double first cousins arise when two siblings reproduce with another set of siblings and the resulting children are related to each other through both parents' families. Double first cousins share both sets of grandparents in common and have double... ---
**Author:** ![echoreply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/echoreply/32/3641_2.png) [@echoreply](https://boards.straightdope.com/u/echoreply)\ **Post date:** [March 24, 2022, 10:42pm UTC](https://boards.straightdope.com/t/what-do-you-call-this-familial-relationship/961655/32 "2022-03-24T22:42:30Z")
Normal siblings have, on average, a genetic relationship of 0.5. Normal half sibs have, on average, a genetic relationship of 0.25; cousins, on average, are 0.125. So the siblings as described by the OP will have a coefficient of relationship of 0.375, which would make them \frac{3}{4} siblings, which is exactly how [Wikipedia](https://en.wikipedia.org/wiki/Coefficient_of_relationship) lists the relationship. I am not aware of any simple English term for that type of sibling relationship. ---
**Author:** ![kenobi\_65](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kenobi_65/32/13178_2.png) [@kenobi\_65](https://boards.straightdope.com/u/kenobi_65)\ **Post date:** [March 24, 2022, 10:55pm UTC](https://boards.straightdope.com/t/what-do-you-call-this-familial-relationship/961655/33 "2022-03-24T22:55:01Z")
Another vote for “half-brothers,” as they share one parent (their father). The fact that they are also first cousins (being the sons of two sisters) is a curiosity, but I’d imagine that the closer relationship would be the most relevant one. ---
**Author:** ![Marvin\_the\_Martian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/marvin_the_martian/32/2898_2.png) [@Marvin\_the\_Martian](https://boards.straightdope.com/u/Marvin_the_Martian)\ **Post date:** [March 24, 2022, 11:15pm UTC](https://boards.straightdope.com/t/what-do-you-call-this-familial-relationship/961655/34 "2022-03-24T23:15:04Z")
Another source calling them “3/4 brothers”: > **[What is a Three Quarter Sibling?](https://whoareyoumadeof.com/blog/what-is-a-three-quarter-sibling/)** > > In this post, you will learn what is a 3/4 sibling, how much DNA 3/4 siblings typically share, and how to know if you have a three quarter sibling. And another: [https://isogg.org/wiki/Three-quarter\_sibling](https://isogg.org/wiki/Three-quarter_sibling) That gives four scenarios where 3/4 siblings occur, the latter two fairly high on the ick factor: > Three-quarter siblings can occur as a result of the following scenarios: > > ``` > a man has children with each of two sisters (the children are related as half-siblings and first cousins) > a woman has children by each of two brothers (the children are related as half-siblings and first cousins) > a woman has children with both a man and his father (the children are related as half-siblings and half-aunt or half-uncle and half-niece or half-nephew) > a man has children with both a woman and her daughter (the children are related as half-siblings and half-aunt or half-uncle and half-niece or half-nephew) > > ``` ---
**Author:** ![UltraVires](https://avatars.discourse-cdn.com/v4/letter/u/ecccb3/32.png) [@UltraVires](https://boards.straightdope.com/u/UltraVires)\ **Post date:** [March 24, 2022, 11:15pm UTC](https://boards.straightdope.com/t/what-do-you-call-this-familial-relationship/961655/35 "2022-03-24T23:15:36Z")
> [@echoreply](#): > > make them \frac{3}{4} 34\frac{3}{4} siblings, which is exactly how [Wikipedia](https://en.wikipedia.org/wiki/Coefficient_of_relationship) lists the relationship. I am not aware of any simple English term for that type of sibling relationship. As I think more, the term 3/4 sibling would make sense. They have 1/2, undisputed. And if we assume that the parent not in common, the two sisters, would share 50%, on average, of their DNA, we would assume, on average, that Thomas and Patrick share 25% of that, which 50+25=75% or 3/4. Yes, they share completely common ancestors except for one, but that one is a huge one, because it is where he got a full half of his DNA from. ---
**Author:** ![lobotomyboy63](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lobotomyboy63/32/2900_2.png) [@lobotomyboy63](https://boards.straightdope.com/u/lobotomyboy63)\ **Post date:** [March 25, 2022, 1:06am UTC](https://boards.straightdope.com/t/what-do-you-call-this-familial-relationship/961655/36 "2022-03-25T01:06:00Z")
3/4 siblings, as described above. Or maybe think of it this way…if children A and B have two parents in common, they’re full siblings. One common parent means they’re half siblings. But if the husband dies and his brother takes his place, fathering another child, he’s like a half parent in common genetically. Children with 1.5 common parents = 3/4 siblings. > **Levirate marriage** is a [type of marriage](https://en.wikipedia.org/wiki/Types_of_marriages) in which the brother of a deceased man is obliged to marry his brother’s widow. Levirate marriage has been practiced by societies with a strong [clan](https://en.wikipedia.org/wiki/Clan) structure in which [exogamous](https://en.wikipedia.org/wiki/Exogamous) marriage (i.e. marriage outside the clan) is forbidden. It has been known in many societies around the world. and > Levirate marriage can, at its most positive, serve as protection for the widow and her children, ensuring that they have a male provider and protector. Levirate marriage can be a positive in a society where women must rely on men to provide for them, especially in societies where women are under the authority of, dependent on, in servitude to or regarded as possessions of their husbands, and to ensure the survival of the clan. The practice of levirate marriage is strongly associated with [patriarchal societies](https://en.wikipedia.org/wiki/Patriarchal_society). The practice was extremely important in ancient times (e.g., [Ancient Near East](https://en.wikipedia.org/wiki/Ancient_Near_East)), and remains so today in parts of the world. Having children enables the inheritance of land, which offers security and status. [Wikipedia source](https://en.wikipedia.org/wiki/Levirate_marriage) I knew a woman from Iran some years ago. She said the government was very strict—dating as we know it in the West wasn’t really allowed. She was very close to her brother and said they were very affectionate in public, which almost got her thrown in jail because it looked like romantic affection. So, she said, lots of people end up marrying cousins. The reason is that because they’re family, there are often get-togethers in each other’s homes so they don’t have police scrutinizing them. They can get to know each other over a period of time. Of course, “cousin” is a broad term. First cousins, second cousins…once removed, twice removed? Would they run into some inbreeding issues? I googled and if you’d like to read up… > **[CONSANGUINEOUS MARRIAGES AMONG IRANIAN MANDAEANS LIVING IN SOUTH-WEST IRAN |...](https://www.cambridge.org/core/journals/journal-of-biosocial-science/article/consanguineous-marriages-among-iranian-mandaeans-living-in-southwest-iran/810D58BF3E40995C3F4FEAD8B8C35DC3)** > > CONSANGUINEOUS MARRIAGES AMONG IRANIAN MANDAEANS LIVING IN SOUTH-WEST IRAN - Volume 50 Issue 4 I cannot imagine what those family trees look like. Of course there are and have been other groups that keep to themselves, increasing the chances of birth defects and so on. ---
**Author:** ![BobLibDem](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/boblibdem/32/3149_2.png) [@BobLibDem](https://boards.straightdope.com/u/BobLibDem)\ **Post date:** [March 25, 2022, 1:19am UTC](https://boards.straightdope.com/t/what-do-you-call-this-familial-relationship/961655/37 "2022-03-25T01:19:40Z")
That is precisely the story for my mother’s parents. My mother’s mother died and her father married his wife’s sister. They had a run of boys together. These boys were my mother’s half brothers and also her cousins, being children of her aunt-stepmom. Then to her brothers’ children, they are my half-uncles and half first cousins once removed, and we’ve called them cousunkles. ---
**Author:** ![Eyebrows\_0f\_Doom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eyebrows_0f_doom/32/3119_2.png) [@Eyebrows\_0f\_Doom](https://boards.straightdope.com/u/Eyebrows_0f_Doom)\ **Post date:** [March 25, 2022, 2:15am UTC](https://boards.straightdope.com/t/what-do-you-call-this-familial-relationship/961655/38 "2022-03-25T02:15:23Z")
> [@Max\_S](#): > > When Dad re-marries, his wife becomes your step-mom. Patrick used to be a first cousin and half brother but is now also a step-brother. I don’t know why you keep referring to step-brothers. Step-brothers are brothers who are not related by blood. Thomas and Patrick have the same father. ---
**Author:** ![UltraVires](https://avatars.discourse-cdn.com/v4/letter/u/ecccb3/32.png) [@UltraVires](https://boards.straightdope.com/u/UltraVires)\ **Post date:** [March 25, 2022, 2:43am UTC](https://boards.straightdope.com/t/what-do-you-call-this-familial-relationship/961655/39 "2022-03-25T02:43:06Z")
Not to speak for @Max_S but what he is saying is that generally if your father marries a woman not your mother, that woman is your step mother. And children that she has are your step siblings. But I think that is why my earlier definition works. You eliminate the distant relationships and keep looking closer. It would be absurd, IMHO, to call Thomas and Patrick step brothers when the traditional use of that term implies no biological connection at all, and that the term “step” when applied to siblings also implies children prior to the marriage to (the general your) father. ---
**Author:** ![lobotomyboy63](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lobotomyboy63/32/2900_2.png) [@lobotomyboy63](https://boards.straightdope.com/u/lobotomyboy63)\ **Post date:** [March 25, 2022, 3:37am UTC](https://boards.straightdope.com/t/what-do-you-call-this-familial-relationship/961655/40 "2022-03-25T03:37:38Z")
If there are 3/4 siblings, logically speaking could there be 1/4 siblings? I guess you’d need to share only half a parent. Like maybe your father’s brother would sire a child with a woman unrelated to you. Erm, wait, that’s called a “cousin.” > [@BobLibDem](#): > > we’ve called them cousunkles. I have DNA in common with my brother’s son (my nephew) but not with my wife’s brother’s son (my nephew by marriage). Beyond that distinction, though, my WAG is that genetic counselors may just calculate how interrelated people are and not put a traditional label on it. With some of these groups, cousin marriage is a thing. But if a person of a group wants to marry a (first) cousin that’s one thing; if they want to marry a double first cousin, that’s different genetically. But what if they wanted to marry the double cousin’s child? And so on. If Albert is my 3/4 sibling, am I 3/4 uncle to his kids? Would my kids be 3/4 cousins to his kids? Etc. What if I also have a half sister? With some groups it seems very possible that these questions could arise. > A bill to repeal the ban on first-cousin marriage in [Minnesota](https://en.wikipedia.org/wiki/Minnesota) was introduced by [Phyllis Kahn](https://en.wikipedia.org/wiki/Phyllis_Kahn) in 2003, but it died in committee. Republican Minority Leader [Marty Seifert](https://en.wikipedia.org/wiki/Marty_Seifert) criticized the bill in response, saying it would “turn us into a cold Arkansas”.[[149]](https://en.wikipedia.org/wiki/Cousin_marriage#cite_note-149) According to the [University of Minnesota](https://en.wikipedia.org/wiki/University_of_Minnesota)’s _The Wake_ , Kahn was aware the bill had little chance of passing, but introduced it anyway to draw attention to the issue. She reportedly got the idea after learning that cousin marriage is an acceptable form of marriage among some cultural groups that have a strong presence in Minnesota, namely the [Hmong](https://en.wikipedia.org/wiki/Hmong_people) and [Somali](https://en.wikipedia.org/wiki/Somali_people).[[150]](https://en.wikipedia.org/wiki/Cousin_marriage#cite_note-150) [Wikipedia cousin marriage article](https://en.wikipedia.org/wiki/Cousin_marriage) > [@UltraVires](#): > > Not to speak for @Max_S but what he is saying is that generally if your father marries a woman not your mother, that woman is your step mother. And children that she has are your step siblings. On “The Brady Bunch,” Mike and Carol Brady’s children were step siblings…his boys were his from a previous union and had no DNA in common with her girls. Likewise, her girls had a different father, so zero DNA shared with Mike or his boys. But if Mike and Carol had created a child, that would have been a half brother or half sister to the existing six, not a step sibling. Yes? [Obligatory “I’m My Own Grandpa” song.](https://www.youtube.com/watch?v=eYlJH81dSiw) [Previous page](https://boards.straightdope.com/t/what-do-you-call-this-familial-relationship/961655.md?page=1) [Next page](https://boards.straightdope.com/t/what-do-you-call-this-familial-relationship/961655.md?page=3)