can fraternal twins be identical?

Jo - posted on 11/08/2009 ( 47 moms have responded )

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i have 16 month old baby boys. they were 2 placentas and 2 sacks, which doctors told me meant they could not be identical. but i had nurses tell me they could still be identical, depending on when the egg split, resulting in 2 sacks/2 placentas. we have great difficulty telling our babies apart and no one else can. anyone else in the same position?

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Jo - posted on 06/05/2010

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ok an update!! we had our almost 2 year old boys dna tested and sure enough, they are identical! thank you to everyone for your advice and experiences. it's true that if an egg splits very early, it can develope into 2 babies, 2 sacs and 2 placentas. the dna testing company also tests for semi identical, which is what amy lea said. 1 egg, 2 sperm that split leaving the babies with identical maternal dna but same paternal dna as normal siblings. thank youy everyone!

April - posted on 12/12/2009

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My twin boys were in two sack two placentas... our doctor said that they still could be identical if the egg split within 72 hours of conception. We spent around $150.00 to have their DNA tested to see and sure enough they are identical. If you have the money go get the test done.

Jenny - posted on 01/01/2010

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My babies had 2 sacs and 2 placentas and were told that they were most likely fraternal. However, we kept thinking that maybe they were identical. We did a DNA test (very easy cheek swab) and they turned out to be identical. The DNA test is the best way to know for sure. Nurses don't always know and you can't tell by the placenta. Good luck!

Iridescent - posted on 04/28/2010

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There are two types of twins not being mentioned here. One is half identical twins http://en.wikipedia.org/wiki/Half_twin
"Half twins or half-identical twins are the result of a very rare form of twinning in which the twins inherit exactly the same genes from their mother but different genes from their father. Although examples of half-identical twins have been found, the exact mechanism of their conception is not well-understood.

There are several mechanisms by which this might happen:

* two sperm fertilise an ovum, one of the two fertilising a polar body (polar body twinning)[1]
* an ovum splits into identical copies, one containing a polar body, prior to fertilisation, allowing it to be fertilised by two different sperm (also referred to as "polar body twinning")[2][3]
* two sperm fertilise the one ovum, forming a triploid, and then splitting (semi-identical or sesquizygotic twinning)[4]

This situation is not the same as the common form of fraternal twinning, in which two genetically different ova are fertilised by two genetically different sperm. In this case, the ova are genetically identical."

The other is identical boy/girl twins - YES it can happen. http://multiples.about.com/od/funfacts/a...

" * A set of boy/girl twins can only be fraternal (dizygotic). Boy/girl twins can not be identical (monozygotic).

Except....

However, there have been a few reported cases of a genetic mutation in monozygotic male twins. For some reason, after the zygote splits, one twin loses a Y chromosome and develops as a female. The female twin would be afflicted with Turner Syndrome, characterized by short stature and lack of ovarian development. It's extremely rare; less than ten cases have been confirmed. Given the odds, it's safe to assume that 99.9% of all boy/girl twins are fraternal. "

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My twins were (and excuse my spelling) monochorionic and I was told that they could either be born Identical or fraternal, we wouldnt know until they were born. With this type of twin, there are three sacks, and two placentas. There is a sack for each baby and then there is a sack surrounding them.
Our happen to be fraternal, but it could have gone either way. Im not positive of the spelling but possibly if you google it you will get some more information. :)

Melissa - posted on 05/06/2010

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Depending on when the egg split can result in two placentas, two sacs, or one sac, or even conjoined twins. When I was researching twins while pregnant I found a site that said when the egg had to split and when in that time line would result in the different forms of identical twins. There are only a few instances where you know for sure identical or fraternal before birth. Boy/Girl twins = for sure fraternal, Mono-Mono = for sure identical. Everything else is up in the air till they come out and either look so different you know they are fraternal or you get them tested. You can go online and do a search for a test that will tell whether they are identical or not, I have seen them range in price from $250 to $1000 dollars. You can also ask your ped about getting them tested, if there is a reason, like a genetic disorder your insurance may cover it. Also look at their blood type, if it is different then they have to be fraternal.

Shannon - posted on 04/28/2010

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Yes they actually could be.
My husband and I did IVF, and 1 egg died off and the other split...now we have our beautifull identical twins boys.

2 things to keep in mind....
they could be fraternal mirror like Mary kate & Ashley Olsen...different DNA but looking the same. I dont know alot about his but it maybe.....or......
They very well could be indentical twins. It actually depends on when the egg splits whether they share a placenta/amniotic sac etc. but the only way to really get the true answer is to have their DNA tested,,,if there DNA is the exact same then they are IDENTICAL!!! Try to get in touch or have your doctor refer you to a genetisist (spelling??) you may be able to find the answers you are loking for.

Good Luck!!

Rebecca - posted on 04/27/2010

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Well Mary kate n Ashley Olson are Fraternal and i would have never have thought that. I have heard of fraternal looking identical.

Chrisandra - posted on 04/27/2010

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This is all so interesting, I didn't know any of this. I'd like to share my twin story.
I had my twins 4yrs ago. One is a boy, the other a girl. I STILL had people asking me if they were identical! LOL Now this is one thing we all should have learned in biology...Different sexes, fraternal twins.
My roommate in the hospital had naturally occuring triplets. They tested the boys & found that 2 are identical twins and the other is 'the other twin'
Happy twin parenting everyone!

Kristina - posted on 01/05/2010

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It depends on if they came from one egg or two. One egg splitting would make them identical, no matter if they had one or two sacs or one or two placentas. If the babies came from 2 eggs then they are fraternal. That is the only difference! And Fraternal twins are genetic. Where an egg splitting is a gift from God. Hope this helps out a bit.

April - posted on 01/04/2010

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Well, I hate to prove a lot of you wrong but my twin boys were in two placentas and two sacks and my specialist said that if the egg splits within so many hours they can have their own placentas an sacks. We got a DNA test done just to see and they tested them three times and they are identical! So, if you have the extra cash go get a DNA test done. Good luck!

Sharon - posted on 01/04/2010

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I have fraternal 9 year old girls. Everyone, from birth til today, say they are identical. I can sort of see it, but I could always tell them apart.

Kellianne - posted on 01/03/2010

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I've got Fraternal twins and they are TWO eggs TWO sperm which can even sometimes be concieved a couple days apart of each other. I dont think my twins look alike but people who dont know me can never tell them apart. My friend has idenctical twins and her and her partner had major trouble telling them apart, she refused to dress them in different clothes so instead she used 2 put simple things like different coloured stockings or a different vest on each baby it actually helped her and she still does it to this day.

Catherine - posted on 01/02/2010

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if the egg splits early enough identical twins have their own placenta and sac.

Shannon - posted on 01/02/2010

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I heard the same thing. Mine split very late and were in the same placenta & sac so they were definately identical. I think you have have them DNA tested to see if they are identical, if they look alike.

Amy - posted on 01/02/2010

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though many people ask if my girl boy twins are identical....they are definitely not....I say identical means all parts are identical....some fight me on it....and others say Oh!!! The ones who fight me on it say but what if they look alike....I say all their parts.....

Kimberly - posted on 01/02/2010

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At first Megan and Melissa looked exactly alike as they got older they now don't. Megan is taller than Melissa. Melissa has sandy blonde hair, Megan has dark brown. Melissa is skinny and Megan is big boned

Sarah - posted on 01/02/2010

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I too was told my babies with two placentas and two sacks were fraternal, but as they get older they are looking more and more alike. I can tell them apart but no one else can. In talking to others, it seems there is a chance that they could be identical. I know several people who have done the DNA test through the internet and in both cases it confirmed that they were in fact identical. good luck!

Haylli - posted on 01/02/2010

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I think they may not be identical but they may look almost excactally the same. I was told Mary-kate and Ashley the Olsen twins are faternal, they look spot on exact but you never know.

Cathleen - posted on 01/02/2010

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I heard recently at a mother of twins convention that there can be DNA tests telling the answer to that question. Apparently if the DNA markers are exact, then they are identical. Not sure exactly how that would work for B/G.

Jennifer - posted on 01/01/2010

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They can't be fraternal and identical. However, they can have 2 sacs, 2 placentas, and still be identical. This only happens when the fertilized egg splits with in the first 48 hours after conception. If it happens any later than that, you will only have one placenta. :)

Tracy - posted on 01/01/2010

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hi we have the same we were told 2 placentas not identical the nurses couldnt tell the girls apart and we can only tell because one has a birthmark on the side of her face (they said that will go when she is about 4)

Misty - posted on 12/31/2009

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My doctor told me that 1 membrane between the babies meant identical for certain; 2 membranes between the babies (2 sacks) meant possibly fraternal, possibly identical. They sound identical to me if at 16 months you have difficulty telling them apart. Only a DNA test would tell for sure and those are expensive.

Leisa - posted on 12/30/2009

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we too were told that they can be identical having different sac/placenta. our two look identical, but we are sure they are not. as they look like there sister at that age as well. i think it is just the genetics that they look so similar.

Meghan - posted on 12/30/2009

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i wanted to add to molly:

i did alot of research when my girls where born and found that identical twins can look slightly different (dimples) and can be different sizes. it all depends on nourishment and environmental factors (usually in the womb). this can often be causes by (but not limited to) twin to twin transfusion. my daughter cece was always a little larger than her twin sister sadie. their facial features are a little different too. they are identical, i had DNA testing done.

Meghan - posted on 12/30/2009

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Quoting Molly:



The nurse was right. It's extremely rare though. People still try to argue with me that my boys are identical. but they are not. Their facial structures are different and one has dimples (hello impossible for them to be indentical) not to mention different heights and weights, even if its only an inch and a half and 4 lbs different. anyways, if it bugs you you can always do DNA testing!




Kelle - posted on 12/30/2009

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yea when i got my first ultrasound and found out we were having twins. The ultrasound tech said that their were two sacs and two placentas. she said "they are most likely fraternal .. if they are the same sex you can test them later to see if they are identical or not but if they are different sexes they are differently fraternal." they were a girl and a boy so of course my two are fraternal but just pointing out that the tech even said despite 2sacs and placentas they could be identical.

Michelle - posted on 12/25/2009

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I have identical twin girls. They both had their own sack. You can get them tested to check whether they are identical or fraternal.

Liza - posted on 12/23/2009

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my twins each had their separate sacks. once they were born the hospital performed blood testing on my daughters and the placentas and it was determined they were identical.
the 2 sack/placenta thing has nothing to do with whether they are identical or fraternal. it seems like you need to stop seeing that doctor who told you that this could not possibly be a case of identical twins.

Kelle - posted on 12/22/2009

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Quoting Jennifer:

Wiki does a good job explaining mono/di.

http://en.wikipedia.org/wiki/Twin

Basically 2 sacs and 2 placentas doesn't necessarily mean fraternal (non-identical). The vast majority of the time, it is the case though. If they look like they could be identical, no harm in double checking. ^_^


haha i didnt realize someone posted the same link.. sorry.



I also wanted to note that the opposite could happen... what I mean is... their could be fraternal twins that fuse together early on resulting in one person being born with 2 types on DNA.  I say this on TLC I think.. or Discovery Channel well a women was told that her child was not her child because the DNA didnt match.  Then the mother found out its because she had two types of DNA and only one matches her child.



This makes since, doctors will tell you that two placentas can fuse together if they are close together...



http://www.thetech.org/genetics/ask.php?...

Kelle - posted on 12/22/2009

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Technically just because their our 2 placentas and 2 sacs it doesnt mean they are fraternal. Most likely they would be fraternal because its rear for that to happen. The only for sure thing is to so a DNA test. A websites online (linked below) says that twins with two placentas and two sacs are called Dichorionic-Diamniotic (DiDi) twins. It also says that this can happen to 18–36% of all monozygotic (identical) twins when splitting takes place after the third day after fertilization. I have read on other websites that if the egg splits early enough when all the genetic coding hasnt finished yet - you could end up with twins with different sexes (b/g) even though it started with one egg and one sperm. A lot could happen based on when.

http://en.wikipedia.org/wiki/Twin

Jocelyn - posted on 12/20/2009

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When I had my twin boys the doctor told me they were from 2 sacks but there was still a chance that they could be identical. He said that there was a test they could do that would tell me. I knew mine weren't so there was no reason to do the test.

Molly - posted on 12/15/2009

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The nurse was right. It's extremely rare though. People still try to argue with me that my boys are identical. but they are not. Their facial structures are different and one has dimples (hello impossible for them to be indentical) not to mention different heights and weights, even if its only an inch and a half and 4 lbs different. anyways, if it bugs you you can always do DNA testing!

Ciera - posted on 12/14/2009

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your doctor should have educated you a little more on twin production...or at least pointed you to someone else who could. 2 placentas and 2 sacks can mean either way. the only way you know for sure it's identical is if they share both and the only way to know fraternal is either if it's b/g or once they are born if they just look totally different. since your sack and placenta were both separate, they could be either identical or fraternal. identical twins result when you drop one egg during ovulation and the egg is fertilized and shortly after fertilization, the egg splits. (this is something that happens to all cells called "cell division" and turns out wonderful when it produces twins) fraternal twins are the result of the mother dropping 2 separate eggs during the same ovulation cycle and each egg is fertilized by a sperm each. This is basically the same thing as getting pregnant twice at the same time. If you believe your babies may be identical, which is likely if they look so much alike, then there are tests that you can have done that will check everything about them to see if they are. The tests cost money though but if they are already 16 months old, pretty much if they still look so much alike that they are difficult to tell apart, most likely they are identical. time will tell for sure.

Stacie - posted on 12/12/2009

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NO I HAD TWIN BOYS IDENTICAL 1 SACK 1 PLACENTA, BUT I HAVE HEARD YOU CAN ACTUALLY DO GENETIC TESTING IF YOU REALLY WANT TO KNOW FOR SURE.

Donna - posted on 12/12/2009

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I had the same thing 31 years ago. I kept the ID braclets on for 3 months. Now they don't look as much alike. Their grandma could never tell them apart. Mine were actually conceived in two separate months which I was told isn't unusual. I always photoed one on the right so I could remember them after the picture was taken. They are best friends always and a joy to raise.

Jodi - posted on 12/11/2009

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I, too, had 2 placentas and 2 sacs, so I began doing research during my pregnancy on the chances of me having identical twins. What I read is there is still a 20% chance that twins that don't share a placenta or sac, can indeed still be identical. It's all about the timing of when the one fertilized egg (resulting in identical twins) split. If the egg split at day number ?-? (don't remember the timeline), the twins will be identical but not share a "room". I didn't beat the odds, I could tell my twins apart from the time they were born. As others have said, DNA is the only way to determine whether or not your twins are identical. There are websites where you can order a home twin zygosity DNA kit, mail the cheek swab back to the lab, and they will send you the results, probably cheaper than going through some laboratory.

Carolyn - posted on 12/11/2009

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I have a friend who's twin girls are 4yrs old and they are suppose to be fraternal but they are more identical than the average identical twins. You can not tell them apart, and don't get their names right then they move, your really lost with who you're talking too.

Beckie - posted on 12/08/2009

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The only way to be 100% sure is lab work. My twins had only 1 placenta and the hospital still ran the test. They are indeed identical. However fraternal twins cannot be identical. This only happens when one egg is fertilized and then splits. Fraternal twins can look A LOT alike though, they are siblings after all.

Jennifer - posted on 12/08/2009

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Wiki does a good job explaining mono/di.

http://en.wikipedia.org/wiki/Twin

Basically 2 sacs and 2 placentas doesn't necessarily mean fraternal (non-identical). The vast majority of the time, it is the case though. If they look like they could be identical, no harm in double checking. ^_^

Amanda - posted on 12/08/2009

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ok i went and had a look around on this ...... it interested me to know ! so this is what i found : seems your nurse may have just been right ! but only way to know for sure is dna test ..
Fraternal Twins

Fraternal twins are the result when two different eggs (ova) are fertilized by two different sperm. This leads to the development of two separate placentas, each with its own chorion and amnion.

Fraternal twins are more common than identical twins and account for about 2/3 of twin pregnancies.

Identical Twins

Identical twins develop when a fertilized egg splits. Depending on when the split occurs will determine if the twins share a placenta, with either one or two chorions and amnions, or if they each develop their own placentas. In general, the later the spit occurs, the more likely that the twins will share one placenta.

Fraternal vs. Identical Twinning

Even after they are born, it is sometimes difficult to know whether twins are identical or fraternal. It can be easier if they:

share one placenta (identical)
are different sexes (fraternal)
have different blood types (fraternal)
It is harder to know if they are the same sex, have the same blood type, or if there are two placentas, since they could then be either fraternal or identical twins.

Don't be fooled by a fused placenta (fraternal twins), which can look like it is just one placenta, or if the twins don't look alike. Sometimes, factors during the pregnancy, especially twin to twin transfusion syndrome, can lead to identical twins that have very different birth weights and are mistakenly thought to be fraternal. And sometimes, fraternal twins can look enough alike to be confused with identical twins.

If you or your doctors aren't sure of the zygosity of your twins, you can consider having DNA testing done.




hope this helps a little , even tho you still wont know 100% without testing .

Sorrell - posted on 11/08/2009

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Fraternal vs. Identical Twinning

Even after they are born, it is sometimes difficult to know whether twins are identical or fraternal. It can be easier if they:



share one placenta (identical)

are different sexes (fraternal)

have different blood types (fraternal)

It is harder to know if they are the same sex, have the same blood type, or if there are two placentas, since they could then be either fraternal or identical twins.



Don't be fooled by a fused placenta (fraternal twins), which can look like it is just one placenta, or if the twins don't look alike. Sometimes, factors during the pregnancy, especially twin to twin transfusion syndrome, can lead to identical twins that have very different birth weights and are mistakenly thought to be fraternal. And sometimes, fraternal twins can look enough alike to be confused with identical twins.

Angela - posted on 11/08/2009

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No. Fraternal twins are two eggs, two sperm. Identical twins was one egg, one sperm that split like you mentioned.



I had the same issue until they were born. Mine are definitely fraternal because they look different. You may not know without getting a DNA test if they look the same.

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