I have twin girls, age 4.5. They were born with 1 pound difference in weight but since the age of 4 months have maintained the exact same height and weight. They also have the same hair color, eye color, and blood type. They have the same interests and abilities, but different enough personalities. One is left-handed and one is right-handed. One, however, has a dimple in her left cheek, and the other does not. (Neither parent has a dimple though, which I hear makes this dimple the result of a genetic mutation - one we quite like!) One girl's hair also grows more easily than the other, but the hair is the same otherwise, both curly despite the fact that neither parents nor grandparents have curly hair. They were in separate sacks in the womb.
The twin zygosity test is $400.
What are the chances my girls are identical? I've always assumed they were fraternal as twinning runs in my family and only one has a dimple, but the fact that they always stay the same height and weight and these other factors has me wondering. I would appreciate your thoughts!
Sorry - some more twin info. Identical twins can be in the same sack or different sacks. If they were in the same sack it would be much easier to determine, but they weren't, and they also have the same blood type so we can't use that either. I agree it's not worth $400. I'm wondering if this dimple thing is a deal breaker? I realize identical twins are from the same egg, but, like other parents, I actually don't know how many eggs there were to begin with.. My pediatrician says he is not sure about their zygosity, but finds it very unusual for a fraternal twin pair to grow so consistently at the same rate for so many years in a row.
Update Jan 11th - I've just ordered a kit at much less than $400 due to the help of one of our posters. Only $79! We'll know soon. Thanks for your help everyone. I've been putting this off for years because I thought - who cares? But all their mirror image stuff has been intriguing to me lately and I find I just really want to know. I'd still say it's a 75% chance they'll be fraternal.
This website says that its the placenta - shared or seperate- that determines identical or fraternal.
http://www.paternity-answers.com/dna-identical-twin.html
The site also says that the can do tests in 3 days for $80.
M.
I don't think it really matters and I wouldn't waste my money on the test. Twins are supposed to be in different sac in the uterus so that doesn't men anything. Identical twins are from 1 egg. The size and resemblance shouldn't be a shock since they re sisters they will have similar appearances anyway.
Sorry I just don't think it';s a big deal and I can think of a million better ways that money can be spent. :)
I have identical twin boys and they shared a placenta (very rarely do they share a sac and if they do this is a very serious problem). We had the placenta tested at birth to make sure it wasn't two placentas that had fused but it was in fact one placenta so that proves they're identical. More often than not identical twins share a placenta but not always (I read somewhere that 2/3 of identicals share a placenta and 1/3 have two placentas). From what you described it sounds like they could be identical (my identical twins have very very different personalities and one is left-handed and one is right-handed) but the only way to know for sure is to have their DNA tested.
having no real knowledge of this, I would be inclined to say fraternal due to the separate sac issue. Have you asked your pediatrician about it?
Typically, identical twins share one placenta. Did the doctor tell you that? if I were you I would want to confirm even just to satisfy my curiosity. I am an identical twin.
30 percent of twins born with 2 sacks are identical. Mine, 31 years old,
(two sackers), one being right handed, one is left (but also ambidextrious.) Bats and golfs right handed, writes, eats, and catches left handed and says he does not have an eye preference. Lefty has a birthmark. Same weight and height varied only 1/2 inch. Lost teeth in the same weeks, which dentist said was unusual even for identicals. Personalities are different but have the same interests and same friends. There has been no indication that they are not identical so I've gone with it for all these years. We only would do further testing if medically necessary (sharing organs). I completely understand your curiosity.
We know it doesn't matter but you and they will be asked this for the rest
of their lives. Also, when they have children, they would want to know if
heredity (fraternal) or not. Identicals can happen to anyone. They don't
know why an egg splits into two separate embryos. Until you know, you can always answer to the curious, "They are identically special".
It sounds like they are identical. I don't think the dimple is a deal-breaker. My husband's sisters are identical twins and I'm pretty sure their dimples are on different sides. Hair growth rates could be dietary, as well as if they were different weights or heights. My husband's sisters are 14 and one is about 1-2 inches taller than the other and weighs about 10lbs more. Those small differences are from variations in diet and exercise, not their genes. Also, right vs. left handedness is somewhat a learned behavior, so I don't think that can be attributed to being identical or not.
I do know there are varying degrees of identical twins, depending on how early the egg split.
they could be mirror image twins if one is right handed and the other left.
I had identical twins in the same sack (not ideal and very dangerous). But, I knew for sure. Most identical twins are not in the same sack, although many don't realize that. What makes me think your girls are identical is the fact that one is left handed and one is right handed. There is something called mirror twins. Look it up online to learn more. It has to do with what day the egg splits after conception. If it splits a little later in the game, you can have mirror twins. Even later, other things can happen. I suppose they can still be fraternal but there are some studies that think all lefties were a twin and the 2nd was never known of. Who knows but it is interesting to ponder. Congrats on your twins, how fun it must be!
I would say that more than likely they are identical-the dimple has nothing to do with it. My girls were also mono-di. Usually if they are identical and one is right handed and the other left that signifies mirror-image twins. I would ask your ob if anything was documented or what was said about the number of placentas.
Well I am a total novice in this discussion but I will say I have seen identical twins that I could tell apart and that had a very slight height difference. So I would vote for identical!
The only way to tell at this point is to have their DNA tested. It has nothing to do with how they look or what they have in common. If they came from the same split fertilized egg, then they are identical.
My husband is an identical twin. My best friend is a fraternal twin.
In my oldest son's graduating class, there were 8 (!) sets of twins there.
My opinion: it doesn't really matter.
Twins try to find their own identity and like my husband says, "HATE, absolutely HATE being called, 'the twins.' "
So love them for who they are, as 2 beautiful daughters and don't worry.
I don't think it really matters if they are identical or fraternal.
Come up with a clever way to answer stranger's questions, b/c they all feel like they have to know. And they don't.....
Just like all the people who "have to know" where my son's blond hair came from and my husband and I and all the brothers have dark hair.
Blond hair, light eyes, dimples, etc.... are all recessive traits and can come from ancestors without being present/ demonstrated in the parents.
Did you have one or two placentas? If you only had one placenta, they are identical. If you had two placentas, they could be either.
Fraternal. I would say.
Identical, is from the same egg.
I would say fraternal seeing as how separate sacs indicate two eggs and identical twins come from one egg. Your obgyn should know from records.
Separate sacs - fraternal.
The Olsen twins are fraternal too, tho they seem identical!
They could be mirror image identical twins (since one is right handed and one left handed). Or fraternal. Just because one has a mutation, does not mean that they are not identical. Mutations can happen along any of the cell splitting stages. (think cancer- it is a genetic mutation). Just because they were in different sacks, doesn't mean they are not identical.
Does it really matter? Sure it would be nice to know, but what are you going to be doing with the information? I know there are certain studies and other medical issues where it matters if siblings are identical or fraternal.
Even in identical twins there are height and wt differences, so that is not a clear indicator anyway.
Who knows?
When they were born, it should have been noted in the doctors notes if there were one or two placentas, how many sacs etc. From there you should be able to determine what they are. For example, my doctor couldn't tell me 100% but through my own research I found that mine are presumed to be identical. They are Monochorionic-Diamniotic identical twins. I didn't find this out until I read the doc. notes and did research on the internet.
Good Luck.
I always thought that twins running in the family usually meant fraternal. Not sure but thats what I always thought
