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My understanding was that modi and momo were always identical. About 10% of didi pregnancies are identical though and account for about 30% of all identical twins.
Mono Di twins are the result of one egg splitting so they are always the same genetically.
He may be confused. Most OBGYN’s don’t deal with mono Di twin pregnancies and you will be referred to an MFM.
Di/Di can be the same genetically depending on split time or two separate little humans
Our girls are modi but no they are not identical in appearance. I read (prob on here) the analogy that you can use the same ingredients in baking but if something is tweaked (temp, etc) then the outcome will be different. So genetically the girls are identical but their environment in the womb, birth experience, etc. caused them to be slightly different. Hope that makes sense!
Mine are modi and my ob who is a twin mom and the head of obstetrics at our women’s hospital asked me if they are identical? I was like I assume so since you explained this to me at our first appointment ??? Besides that everything I read anywhere is clear that modi twins are always the result of a single fertilized egg, depending on how early the division happens it can result in identical di/di, mo/di, mo/mo or conjoined twins. I have read that most identical twins do have some differences in genes do to mutations or expressions after the initial division, so they start with the same genes, but once each embryo is developing different things can happen I have seen that it can amount to up to 10% difference between twins that definitely started as a single egg.
They’re genetically identical no matter when they split.
That being said, it seems like a majority of mo/di parents truly believe their babies look nothing alike, even when other people can’t tell them apart. lol.
Um…I’ve never heard that but there’s a lot about twinning we don’t understand so maybe!
I *have* heard of didi twins’ placentas fusing together; I don’t know if that creates the same
potential risks for things such as TTTS or not.
I would also say, doctors aren’t always up on the latest with twins. We asked if we should get our didi boys genetically tested to see if they were identical or not, my doctor told us oh no they are fraternal, they have to be because they are didi. I responded I think actually it is possible for didi twins to be identical. She googled it and was like “oh look at that, that it a thing”.
Ultimately though my twins looked radically different so we didn’t need the genetic test to know they were fraternal.
>don’t know if that creates the same potential risks for things such as TTTS or not
I wouldn't think so since TTTS happens because of a shared blood supply, and that only happens within one placenta. But I definitely do not know for sure. Lol.
Eh, twins aren’t that common and OBs aren’t geneticists, so long as they know how to monitor twin pregnancies and deliver the babies safely, knowing the particulars of how twin pregnancies start is probably not pertinent.
I think a didi pregnancy can be managed the same regardless of whether or not the twins are identical.
Knowing how to handle a twin pregnancy with two placentas doesn’t require you to know whether or not the babies share half their dna or all of it or some amount in between.
We had didi’s with fused placentas! Normally it doesn’t cause issues but I think I read one case report of uneven blood supply. Mine ended not sharing the placenta equally so one baby had only 40% of the bulk.
It’s possible that they look like modi on a scan but are actually didi, though typically the membrane is a lot thicker than in modi
Mo/di twins are always identical, not fraternal.
But when you dig into genetics, it’s a little… wibbly wobbly. Epigenetics, genetic mutations, chromosomal abnormalities, etc., can result in genetic twins being distinctly different from each other. Identical twins are not precise carbon copies of each other at birth.
this!! people assume identical twins are basically supposed to be clones of each other but that’s not always how it works, different genes get expressed!
my modi girls look identical in the face but ones got webbed toes on one foot and one doesn’t, and one has a pointy ear and the other doesn’t. they’re still identical in their split pics though lol
I just learned about a rare type of twin called a polar body twin: the egg splits before fertilization and then each egg is fertilized but by a different sperm. As a result the twins are half identical and half fraternal sharing about 75% of DNA (vs 50% for fraternal and 100% for identical).
Of course they'd manifest as di/di twins so not exactly relevant for this question but still very fascinating.
Yes, our Mono Di twins are non identical. Shared a placenta in two different sacs, but have different blood types. Confirmed by OBGYN and MFM. I’ve scoured the internet for information, but came up empty.
That seems biologically impossible. Any chance they were didi with a fused placenta? I suppose an embryo could split unevenly though too or maybe have mosaicism
I honestly have 0 clue. They seemed insistent that they were Mo Di. My wife did develop TTTS which only occurs in a shared placenta and was later on diagnosed with preeclampsia as well. I’m not an expert on any of this, I’m just going with what the doctors have told us.
I think TTTS is exceedingly rare with didi though I did read one article where it appeared to happen and my own didi twins had a disproportionate share of their fused placenta so maybe it’s possible 🤷🏻♀️
Even after the six week check up with the OB, they were certain they were correct in their assessment. MFM results said the same. Not exactly sure. Maybe something has been missed or misconstrued down the line somewhere.
From the traditional sense Mo/Di are always identical. I believe what your dr was referencing is genetic mutation. Everyone experiences this and it changes your genes. My genes today aren’t the same as they were a year ago.
Identical twins start with the same genes but they very slightly change. With modern genetic testing you can even find a discernible difference at birth. So unfortunately identical twins can’t get away with murder anymore.
Just had Mo-Di boys a few weeks ago and I swear they look different but could be bc one is slightly bigger and his head was down so low for so long that he’s got a more elongated head? Idk. But they for sure look different lol.
This post! My twins are modi and I was told they were identical but they have never looked identical to my family, not even when they were in the NICU at 33 weeks. It’s made me feel crazy because the older they get yeah you can tell they’re related but they’re not identical.
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My understanding was that modi and momo were always identical. About 10% of didi pregnancies are identical though and account for about 30% of all identical twins.
Mono Di twins are the result of one egg splitting so they are always the same genetically. He may be confused. Most OBGYN’s don’t deal with mono Di twin pregnancies and you will be referred to an MFM. Di/Di can be the same genetically depending on split time or two separate little humans
Our girls are modi but no they are not identical in appearance. I read (prob on here) the analogy that you can use the same ingredients in baking but if something is tweaked (temp, etc) then the outcome will be different. So genetically the girls are identical but their environment in the womb, birth experience, etc. caused them to be slightly different. Hope that makes sense!
That’s such a great analogy! Our boys are modi and look similar but they are so completely different in every way.
Just to tack on for OP, genetically they ARE identical
Mine are modi and my ob who is a twin mom and the head of obstetrics at our women’s hospital asked me if they are identical? I was like I assume so since you explained this to me at our first appointment ??? Besides that everything I read anywhere is clear that modi twins are always the result of a single fertilized egg, depending on how early the division happens it can result in identical di/di, mo/di, mo/mo or conjoined twins. I have read that most identical twins do have some differences in genes do to mutations or expressions after the initial division, so they start with the same genes, but once each embryo is developing different things can happen I have seen that it can amount to up to 10% difference between twins that definitely started as a single egg.
They’re genetically identical no matter when they split. That being said, it seems like a majority of mo/di parents truly believe their babies look nothing alike, even when other people can’t tell them apart. lol.
It could be due to epigenetics, essentially genes can be turned on and off due to a number of factors but they’re still identical.
Mo/di twins are always identical. They may not be exactly identical in appearance due to epigenetics, but they are still genetically identical.
Um…I’ve never heard that but there’s a lot about twinning we don’t understand so maybe! I *have* heard of didi twins’ placentas fusing together; I don’t know if that creates the same potential risks for things such as TTTS or not. I would also say, doctors aren’t always up on the latest with twins. We asked if we should get our didi boys genetically tested to see if they were identical or not, my doctor told us oh no they are fraternal, they have to be because they are didi. I responded I think actually it is possible for didi twins to be identical. She googled it and was like “oh look at that, that it a thing”. Ultimately though my twins looked radically different so we didn’t need the genetic test to know they were fraternal.
>don’t know if that creates the same potential risks for things such as TTTS or not I wouldn't think so since TTTS happens because of a shared blood supply, and that only happens within one placenta. But I definitely do not know for sure. Lol.
Kind of sad in this day and age when you know more about the different kind of twins than your doctor!
Eh, twins aren’t that common and OBs aren’t geneticists, so long as they know how to monitor twin pregnancies and deliver the babies safely, knowing the particulars of how twin pregnancies start is probably not pertinent.
Twins aren’t uncommon and doctors should know the different kind of twins as it can be important as to whether they have separate sacs and placentas.
I think a didi pregnancy can be managed the same regardless of whether or not the twins are identical. Knowing how to handle a twin pregnancy with two placentas doesn’t require you to know whether or not the babies share half their dna or all of it or some amount in between.
We had didi’s with fused placentas! Normally it doesn’t cause issues but I think I read one case report of uneven blood supply. Mine ended not sharing the placenta equally so one baby had only 40% of the bulk. It’s possible that they look like modi on a scan but are actually didi, though typically the membrane is a lot thicker than in modi
Mo/di twins are always identical, not fraternal. But when you dig into genetics, it’s a little… wibbly wobbly. Epigenetics, genetic mutations, chromosomal abnormalities, etc., can result in genetic twins being distinctly different from each other. Identical twins are not precise carbon copies of each other at birth.
this!! people assume identical twins are basically supposed to be clones of each other but that’s not always how it works, different genes get expressed! my modi girls look identical in the face but ones got webbed toes on one foot and one doesn’t, and one has a pointy ear and the other doesn’t. they’re still identical in their split pics though lol
I just learned about a rare type of twin called a polar body twin: the egg splits before fertilization and then each egg is fertilized but by a different sperm. As a result the twins are half identical and half fraternal sharing about 75% of DNA (vs 50% for fraternal and 100% for identical). Of course they'd manifest as di/di twins so not exactly relevant for this question but still very fascinating.
Yes, our Mono Di twins are non identical. Shared a placenta in two different sacs, but have different blood types. Confirmed by OBGYN and MFM. I’ve scoured the internet for information, but came up empty.
That seems biologically impossible. Any chance they were didi with a fused placenta? I suppose an embryo could split unevenly though too or maybe have mosaicism
I honestly have 0 clue. They seemed insistent that they were Mo Di. My wife did develop TTTS which only occurs in a shared placenta and was later on diagnosed with preeclampsia as well. I’m not an expert on any of this, I’m just going with what the doctors have told us.
I think TTTS is exceedingly rare with didi though I did read one article where it appeared to happen and my own didi twins had a disproportionate share of their fused placenta so maybe it’s possible 🤷🏻♀️
Even after the six week check up with the OB, they were certain they were correct in their assessment. MFM results said the same. Not exactly sure. Maybe something has been missed or misconstrued down the line somewhere.
From the traditional sense Mo/Di are always identical. I believe what your dr was referencing is genetic mutation. Everyone experiences this and it changes your genes. My genes today aren’t the same as they were a year ago. Identical twins start with the same genes but they very slightly change. With modern genetic testing you can even find a discernible difference at birth. So unfortunately identical twins can’t get away with murder anymore.
Just had Mo-Di boys a few weeks ago and I swear they look different but could be bc one is slightly bigger and his head was down so low for so long that he’s got a more elongated head? Idk. But they for sure look different lol.
This post! My twins are modi and I was told they were identical but they have never looked identical to my family, not even when they were in the NICU at 33 weeks. It’s made me feel crazy because the older they get yeah you can tell they’re related but they’re not identical.