# Are you a multiple that had multiples?



## Northstar78 (Feb 13, 2011)

Just curious about this one-I'm a triplet and my younger sister almost had twins. Does it really run in the family or are there other factors at work?


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## LivingSky (Aug 13, 2010)

Yes, fraternal twins are an inherited trait. Identical are not.

It is a genetic predisposition to ovulate multiple follicles at once rather than just one per cycle, and this is passed down - however my understanding is that it is one of those things that skips a generation. My husband is a fraternal twin - if we have a daughter, she would be at high risk for having fraternal twins when she has children. However, my DH's twin sister is not at a higher than normal risk for twins (and in fact has had three normal singleton pregnancies) but her daughters will be.

This does NOT take in to account mulptiples that are conceived through IVF or other fertility treatments - multiple pregnancies conceived through IVF would not lead to higher risk of multiples in later generations.

Does that help?


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## capretta (Mar 23, 2010)

Quote:


> Originally Posted by *LivingSky*
> 
> Yes, fraternal twins are an inherited trait. Identical are not.
> 
> ...


I'm certainly no expert, but that is _not_ my understanding of how it works. Well, not completely. Yes, only fraternal twins are genetic, but I am pretty sure the "twin gene" is only passed through female lines. I've also never heard/read anything about it skipping generations. So I would think that you've got it backwards - in fact, your SIL is more likely to have twins than your daughter is.
Quote:


> Originally Posted by *Northstar78*
> 
> Just curious about this one-I'm a triplet and my younger sister almost had twins. Does it really run in the family or are there other factors at work?


In addition to fertility treatments, maternal age also affects likelihood. Here is a short article about the odds of twins.


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## ValH (Aug 19, 2010)

Quote:


> Originally Posted by *LivingSky*
> 
> Yes, fraternal twins are an inherited trait. Identical are not.
> 
> ...


I have heard that twins do skip generations, but I don't know if there's scientific evidence on it. I've seen it in my family, though. My grandmother conceived twins (but miscarried one), but none of her children had twins at all... but then several of her grandchildren have had twins. So in my family, it did indeed skip a generation. Now I'm waiting to see if it skipped me...


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## Northstar78 (Feb 13, 2011)

Well, I'm an identical twin and we three are all girls. I think I read too that coming off bcp increases your chances as does your age (I'm 32) so we'll have to wait and see!


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## LivingSky (Aug 13, 2010)

Quote:


> I'm certainly no expert, but that is _not_ my understanding of how it works. Well, not completely. Yes, only fraternal twins are genetic, but I am pretty sure the "twin gene" is only passed through female lines. I've also never heard/read anything about it skipping generations. So I would think that you've got it backwards - in fact, your SIL is more likely to have twins than your daughter is.


The genetic predisposition is passed through the X chromosone - which both men and women carry. So DH's X chromosone would still carry that pattern - passing it on to his daughter (but would NOT pass on to a son). That part I'm 100% sure of







The skipping generation is what I've heard but I don't know what the reasoning behind that is. But my SIL has had 4 pregnancies, 3 children, and every one has been a singleton pregnancy. I guess we'll see though once her daughters are a bit older! And of course even in women who are predisposed to twins, it's still not guaranteed, so who knows whether SIL is really predisposed and just hasn't ended up with twins.


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## bcblondie (Jun 9, 2009)

Your husband being a twin wouldn't affect your daughters chances of having twins. He makes sperm. Not eggs. So he could not pass on teh trait of multiple ovulation.

If a woman naturally conceives fraternal twins, those twins would be more likely to also have twins (assuming they are girls) because they likely carry that tendancy to release more than one egg per cycle. Even if the twins have a sister that is not a twin, there's a good chance she carries that trait as well. And she could have twins as well.

I've found no research supporting the skipping a generation thing. That's probably an old wives tale that developed since the trait was passed on through generations, but the chances of actually having twins is still only like 2%, depending where you read. So it's likely that a generation or 2 would be missed and then somewhere along the line it happens agian.

I have 2 friends who are twins, and their sister did have twins herself. My friends have not had babies yet but I'm eager to see if they have multiples.


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## springbabes (Aug 23, 2003)

My mom's cousin is a twin that had twins, so it didn't skip a generation for her.


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## LivingSky (Aug 13, 2010)

Quote:


> Originally Posted by *bcblondie*
> 
> Your husband being a twin wouldn't affect your daughters chances of having twins. He makes sperm. Not eggs. So he could not pass on teh trait of multiple ovulation.


That made me giggle







Sperm versus eggs don't make a difference with genetics - the male still passes on half his genetic code. While eggs can only carry an X chromosone, sperm can carry either an X (making a female baby) or a Y (making a male baby). So a man can pass certainly pass on female genetics that he himself does not experience.
Quote:


> Of the factors that influence multiple birth, there is only one that could be identified as genetic or explained by family history: hyper ovulation. Hyper ovulation is the tendency to release multiple eggs during ovulation, increasing the chances of conceiving dizygotic (or fraternal) twins. So, in families where the women have a gene for hyperovulation, genetics would sufficiently explain an increased presence of fraternal twins.
> 
> However, only women ovulate. So the connection is only valid on the mother's side of the family. *While men can carry the gene and pass it on to their daughters*, a family history of twins doesn't make them any more likely to have twins themselves.


That is from this link - which talks about twins skipping a generation only being true with male offspring (since males can't directly influence their own children being twins). http://multiples.about.com/od/pregnancy/a/familytwin.htm

I think the confusion on this subject is that my DH being a twin doesn't mean he is more likely to have twins - because his genetics don't make ME ovulate more than one egg. But his X chromosone gets passed on to his daughters, so they will be more likely to hyperovulate.


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## Northstar78 (Feb 13, 2011)

So if I'm reading through this correctly, it's the female chromosomes that are responsible for multiples? My friends (both girls) are twins and one of them has two adorable little boys that aren't twins. My younger sister who almost had twins has a daughter. I'm an identical twin and a triplet, so if we have a girl, then the chance goes up for multiples?


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## LivingSky (Aug 13, 2010)

Quote:


> Originally Posted by *Northstar78*
> 
> So if I'm reading through this correctly, it's the female chromosomes that are responsible for multiples? My friends (both girls) are twins and one of them has two adorable little boys that aren't twins. My younger sister who almost had twins has a daughter. I'm an identical twin and a triplet, so if we have a girl, then the chance goes up for multiples?


It's the female who is responsible for multiples, yes. But it doesn't impact what sex the multiple children would be. It just means that you (because you have a fraternal twin) would be more likely to have twins. If you have a daughter, she would be likely to have twins as well. If you have a son, then his daughters would be more likely to have twins (but he himself would not be more likely to have twins).

Clear as mud?









Breaking it down per person:

You are more likely to have a multiple pregnancy, because you have a fraternal twin (that you have an identical twin does not impact your chances either way). If you have a multiple pregnancy, the children could be either male or female or one of each.

If you have a daughter (or daughters) she would be likely to have a multiple pregnancy as well.

If you have a son, then he is NOT more likely to have a multiple pregnancy with his partner. However, if he has a daughter, she will be more likely to have a multiple pregnancy.

So only the mother can impact whether she ovulates more than one egg at a time, but the genetics that make her hyperovulate can come from either (or both) her mother or her father.

Still clear as mud, I think







It's a complicated subject, but it's definitely an interesting one!


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## bcblondie (Jun 9, 2009)

Ok... so... what you're saying is the man could carry the gene that affects multiple ovulation, even though HE doesn't make eggs himself, he could pass that trait to his daugher?


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## LivingSky (Aug 13, 2010)

Quote:


> Originally Posted by *bcblondie*
> 
> Ok... so... what you're saying is the man could carry the gene that affects multiple ovulation, even though HE doesn't make eggs himself, he could pass that trait to his daugher?


Yep, exactly!


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## capretta (Mar 23, 2010)

Hmm, ok. Thanks for the explanation! So really your SIL and daughter should have about the same chances, all other things being equal.


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## bcblondie (Jun 9, 2009)

Whoa.

I mean, I could google. But do you have any links?


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## BathrobeGoddess (Nov 19, 2001)

I;m moving this to the main fertility board.


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## ValH (Aug 19, 2010)

LivingSky - Thanks for the explanation - that makes much more sense now.  So basically the trait for twins on my side of the family (through my dad's family) could have been passed to me through my dad's X chromosome... and if DH and I have a girl, the twin trait from my side and DH's side could be passed to her. Yep, clear as mud! Seriously, thanks for all the info.


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## justKate (Jun 10, 2008)

Wow, interesting. Not to derail the thread, but I'm finding a lot of older people thought they were identical twins but don't know for sure...

My best friend is pg w/twins, and her mother is a twin. Her mother (in her 60's) believes she is an identical twin, but how would she really know? I'm guessing an U/S showing that they shared a bag of water would mean identical, but obviously they didn't have that when her mom was born....


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## bcblondie (Jun 9, 2009)

I think there's a blood test that can tell you if you're identical.


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## justKate (Jun 10, 2008)

Quote:



> Originally Posted by *bcblondie*
> 
> I think there's a blood test that can tell you if you're identical.


Yeah. But what if only one twin is alive? Like my Gpa, for example, was a twin, and they thought they were identical, but the other twin was given away, and then died in his 60's.... I know, too many variables, but I just wonder. The given away part was because it was the Depression and they couldn't "afford" two babies.


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