Fraternals, ID, and genes

So help me put this to rest once and for all. Can frats be genetic? ID's be genetic or are they always flukes?

Links to studies would help.

Thank you so much

 

I was told by the dr. that frats are always genetic, SOMEWHERE down the line (not the male's line though, because its all eggs). I always thought ID was alwaysa fluke, but a friend of mines entire family is full of ID twins. So maybe their eggs just split easier, and thats genetic? I don't know. Wish I had facts for you though

 

Frats can't always be genetic AFAIK.

 

All I can tell you for sure is that I am having ID twins, and neither my husband nor I have any twins closer than our grandparents generation. His grandma was an ID twin, but I know that's not supposed to count, anyway. <shrug> I've been meaning to ask about this, too, on here. I have asked my OBs a time or two, and they all say IDs are not genetic.

 

Our friends r fraternal twins and their dad Was a fraternal twin. I still believe identicals aren't flukes. I know families where identicals run in their family.


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I don't think the fact that their dad was a frat makes a difference as it's the wife who had to drop two eggs.

 

Yeah thats true.. Ive always wondered about the genes with twins and all. I mean alot of people argue that twins happen every 2 generations. Like since im a twin, i wont have twins but my kids could? I dont know how true it is. Cause i know many people that are twins that had twins themselves.

 

Yeah I dont know really. I mean an egg is an egg, why would it be a fluke? they would have to be something in the "genes" that makes it split right?

 

Another question I have is regarding age of the mother... you know, how the older the mom is the more likely that twins will occur? So I am in my mid 30s which is about the age that twins supposedly become more common, but I thought that only applied to frat twins. But here I am pregnant with identical.

One theory I had is, what if a family line of women have a tendency to marry late, then they'd seem to be more prone to twins if twins happen more later in life.

 

Well our mum had us when she was 40, she had a couple miscarriages. Maybe when u get older the eggs become weaker and spilts easier? if that's possible? We r identical twins.


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It could be that for identicals,and maybe for fraternals when you are older too and SOMEWHAT close to menopause, the body could be producing more eggs causing 2 to drop instead of 1? My grandma started our families trend in her 10th pregnancy and had frat. twins in her 30s (no prior twins in the line anywhere), then my aunt had frat twins in her 20s, and then me at 18.

 

They say ids aren't genetic but we have 5 sets in 4 generations! That's out of 20 sets total

 

Ive done a little research just by googling different key words involving twins.

I found that fraternal twins are said to be hereditary on the mothers side, because there is a gene that is passed on, that causes the woman to release more than one egg. Most fraternal twins are born from two completely separate fertilized eggs.

However, I *BELIEVE, (not 100% sure) that fraternals can also be born from one egg that splits..depending on WHEN the egg splits. Is this true?

When I was doing my mini research about it, there were a lot of statistics listed regarding your chances of having twins (or higher multiples) based on where you live, your age, race, birth order, etc. It also said that female twins have X% chance of having a set of twins themselves. I forgot the actual percentage.

Everything I found also said that identicals are flukes, but I dont necessarily believe that either. As pp's have said, there are some families that have several sets of Identical twins, so it seems that there is something in the genes that causes the eggs to split.

Personally, I have bg fraternal twins. My DF brother has a set of ID girls.. so obviously myself, and DF SIL have no relation and both of us have twins. ETA, HIS family thinks the twins come from their side, since her and I both have twins by brothers. :blush: Little do they know. heehee. I couldnt even try to discuss it with them, as they have NO CLUE.

 

Fraternal twins CAN be heriditary - some women have a gene that causes them to always release multiple eggs every month. Any woman carrying such a gene is more likely to have fraternal twins. A woman with the gene (she herself being more likely to have twins) can pass it on to ANY offspring. Her male children who carry the gene aren't any more likely to have fraternal twins, but THEY can pass the gene to any daughters (which is why fraternal twins sometimes "skip" a generation - the gene is passed on to a male offspring, who later passes it to his female offspring)

Fraternal twins can also be just random - a fluke where you release two eggs in one cycle, but not necessarily due to any heriditary factor. This is more likely to happen the older you are. (I think there are a few other factors that influence this "random" fraternal twinning, but I don't remember what they are)

Identical twins are thought to be completely random, but like others have mentioned there are some families that have several sets of identical twins. Nobody has ever found anything they can specifically link to causing eggs to split.

I think teh only way to have "fraternal" twins from one egg is to have the very rare sceneario of 'half identical' twins - when the egg splits prior to fertilization, then each 'half' of the egg gets fertilized by a different sperm. Otherwise, 1 sperm + 1 egg = ALWAYS identical twins.

 

I think you might be thinking of di/di identical twins. This happens when the egg splits earlier so each baby gets their own everything- placenta and amniotic sac. They are not fraternal, though- they are identical, but can sometimes appear to be frat because that's how frats present. The only way to determine their zygosity is a dna test (unless their gender, blood type, hair or eye color is different.)

 

wow that's really interesting, but yeah the theories do seem possible and realistic


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yes me too. An egg that spilts always results in identical twins


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I have a couple of theory about my ID boy twins. I got pregnant in Oct 08, right around the time I got my flu shot. There ya go, flu shots cause twins. lol
Okay dumb, here's my other theory, I was visiting in the Appalachian moutains when I got pregnant, soooooo, higer altitude and higher demand on my body for oxygen caused twins. lol
Okay, I'm just being silly.
We don't have any IDs in our family, so I'm leaning towards fluke.

 

Is that true? That they are identical? Because I have di/di twins, and like you said seperate placenta & amniotic sac. However the doctors only told me that the only way to know if they were ID or Frat was to get the DNA test done (because we don't know what there blood type is, hospital didn't test I guess), but they look just alike except for the shape of their heads/faces. Hmm.. guess we will find out soon..

 

Di/Di can be identical. All fraternals are di/di unless there is a placenta fusion or something. In identicals, if the embryo splits early enough they will have their own placentas and amniotic sacs. The only way to know is with a test. My boys are Di/di IDs, we did a test because they looked way to much alike in our opinions.

 

Yes it is. I found this video about Identical twins and it explains everything you need to know.
It's here
http://www.youtube.com/watch?v=PgbkJ6J77Lc

 

You should post pics and we can play the "are the ID or Frats" game !! You'll get your answer. :ibiggrin:

For me I would say my ID's were either my age (I was 37 when I got pg with my boys) OR just a fluke, There are NO other twins in the family. My grandmother was said to be a twin .. but we have no idea if she was ID or Frat.

 

If there are women who have a tendency to have their eggs split (think more than one set of ID twins, such as my sil), wouldn't it make sense that her daughter might inherit the same tendency? Is it an overdose of hormones? Or maybe weaker hormones/eggs?

You mean 20 sets, so 15 frats and 5 ID? Wow.

 

Yes we have 5 sets just in the twins generation(in order of birth): frat g/g, id g/g, frat b/b, id b/b, frat b/g. And that's just on my mom's side of the family.

 

You asked for a link, I found this: http://www.troupsburg.com/lori/blog/2009/05/identical-twins-and-heredity.html

I found it pretty garsh darn interesting. This is because we have ID girls and my husband is an ID twin as well.

 

Thank you. Will read it tomorrow when I don't have cotton balls between my eyes.

 

Wow I enjoyed reading this.. very interesting. It would be interesting to see if anything comes out in the study - like a possible answer

 

Wow. how cool. See point made, there has to be something in the genes when it comes to twins in families.

 

You can prove statistically that IDs are a fluke. 1:250 or so are the odds regardless of where you are in the world. That doesn't mean that there aren't a very few women (a statistically insignificant number) who have a genetic predisposition for eggs that like to split when they divide. However, saying that because those few women exist means that IDs are caused by genetic predisposition is applying a rule based on the fluke rather than the norm. There are only a few families in the entire world like the one mentioned with 20 sets, 5 being ID.

 

Are you ID or frats? If you are frats, your mother could have passed the gene to you an your sister and you would be at a higher chance of having twins. If you had frat twin boys, they would carry and could pass the gene to their daughters, but would not have a higher chance to having twins themselves, because it would be on the females side.

If the egg splits after it has been fertilized they would be ID, but could still have two of everything depending on when the split occured. I also wonder about enviromental elements. I am in a moms group that I joined when my oldest was a few weeks old. There are 17 of us, and most have had their 2nd child (or third) in the past few months. Out of 17 of us, 3 just had boy twins in the past 4 months. All 3 of us also have 2 year old boys. What are the chances? None of them were as a result of fertility, and none have history of twins that we are aware of. Weird....

We are in the same situation. We are planning on doing a DNA test in the next few weeks to find out. My heart says they are ID. You can see them on myblog and let me know what you think! :ibiggrin:

 

They look ID to me, and sooooo cute!!! My girls had the girl version of those new years' onesies too

 

We are ID, we had TTTS and our Mum had us later in life, after 2 other pregnancies so that probably contributed to it. But we have ID Twin Girl Cousins on our Mum's side.. strange hey.. I know Twins ran way back on mums side but I think they were Frats.