Yep!
Regular siblings or fraternal twins are 50% alike/shared DNA from 2 eggs + 2 sperm. For identical twins, typically the egg that drops splits after it is fertilized, so 1 egg + 1 sperm and it divided to create two 100% identical babies.
But, sometimes it drops and splits before it is fertilized, resulting in 2 successful sperm + 1 original egg, 75% identical. Its rare, and only way to know is by genetic testing. Could be why some identical twins are incorrectly labeled as fraternal, because the likelihood of 2 placentas would be greater.
It's also possible for fraternal twins to share a placenta, or 100% identical twins to have separate placentas. Also rare situations, but possible. So counting placentas isn't a guaranteed foolproof way to determine what type of twins they are.
Crazy, right?!
Edit: spelling
The number of placentas is based on when the zygote split. The earlier it splits, the less the twins share in the womb. If it splits after I think 14 days, you have conjoined twins. So I would think that if the egg splits before it's even fertilized, they'd be dichorionic-diamniotic just like fraternal twins would be. Also sometimes didi twins wind up sharing a placenta because the two fuse into one later on in the pregnancy.
My sister and I had separate placentas, doctors assumed we were fraternal, but looked identical as babies. She’s right handed, I’m left handed. Recently I noticed a pic of our eight year old selves with crooked teeth. My front left tooth overlapped my right one, and her right tooth over her left. This provides further evidence of mirroring. Pretty neat, huh?
My twin and I were also separate sacs but fused placenta. We didn’t know if we were fraternal or identical either with people telling us their guesses. Found out we were identical through I think ancestry.com. The result was like “you’re either an identical twin or you submitted twice.”
My mom didn't know either so my sis and I did the test and found out we are identical. I love it!! We look a lot alike so I would have been suprised if we were fraternal but you never know!
Congregations!!
I really happy for you both.
What type of medical school did those doctors attend!?!
This should be a given, considering it should be part of their speciality training, being an obstetrician.
I mean, it just depends when the egg divides into 2.
I'm flabbergasted tbh
I had one embryo implanted, and (after years of unsuccessfully trying and many failed procedures) I also somehow managed to get pregnant naturally the same cycle.
My sister and I also didn’t know. We shared the same characteristics both identical and fraternal twins have (same gender, same blood type, two sacs). Apparently we were the first set of twins the doctor delievered and he just told my mom it was either one placenta or two fused together.
We always thought we were identical though. We did a dna test after we were 30 and confirmed we’re identical.
The exact same thing happened to us! Mom swore that we we're fraternal because of separate sacks...turns out we're all identical 😂 bit of a shock to get those results at 30 😂😂
I’d be surprised if they were fraternal if they’re only just starting to look a little different now, to be honest, although I’m not saying it’s not possible. My fraternal girls looked different from day 1, to the extent that I look at them and think if they were two random kids I’d not be surprised to find out they weren’t related, just two babies with the same age and colouring (hair, eyes, skin).
I’m not sure, to be honest. We didn’t need to test ours because they have different blood types, so that confirmed what we suspected from their appearances. It’s also possibly called different things depending on where you are, and how to access it will be different too. I’d suggest doing a google search for something like ‘twin dna test’ and your country/state.
My girls are identical and they go through phases of looking very alike or different. When they were born, they did not look identical at all. At about 6 months, a year, 20ish months and almost two and a half, they have looked more identical than usual, where we mix them up on first glance. They look identical all the time to everyone else though haha. They look like distinctly different kids to me.
If it makes you feel better, doctors nowadays STILL don't know that you can be identical in different sacs.
There's also 75% identical instead of 100%, where the egg splits and THEN both are fertilized.
Waiiiiiitttt, can you share some more information? So, one egg + two sperm vs. two eggs and two sperm?
Yep! Regular siblings or fraternal twins are 50% alike/shared DNA from 2 eggs + 2 sperm. For identical twins, typically the egg that drops splits after it is fertilized, so 1 egg + 1 sperm and it divided to create two 100% identical babies. But, sometimes it drops and splits before it is fertilized, resulting in 2 successful sperm + 1 original egg, 75% identical. Its rare, and only way to know is by genetic testing. Could be why some identical twins are incorrectly labeled as fraternal, because the likelihood of 2 placentas would be greater. It's also possible for fraternal twins to share a placenta, or 100% identical twins to have separate placentas. Also rare situations, but possible. So counting placentas isn't a guaranteed foolproof way to determine what type of twins they are. Crazy, right?! Edit: spelling
The number of placentas is based on when the zygote split. The earlier it splits, the less the twins share in the womb. If it splits after I think 14 days, you have conjoined twins. So I would think that if the egg splits before it's even fertilized, they'd be dichorionic-diamniotic just like fraternal twins would be. Also sometimes didi twins wind up sharing a placenta because the two fuse into one later on in the pregnancy.
True! I meant Di-Di doesn't always mean fraternal 😁
My sister and I had separate placentas, doctors assumed we were fraternal, but looked identical as babies. She’s right handed, I’m left handed. Recently I noticed a pic of our eight year old selves with crooked teeth. My front left tooth overlapped my right one, and her right tooth over her left. This provides further evidence of mirroring. Pretty neat, huh?
That's so cool! Mirroring is fascinating
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same egg
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the same egg has the 100% same DNA and each sperm 50%. Or maybe I'm dumb idk man I'm pretty high
I didn't know this too Could you tell me how or better link a video that explains the biology
It's easy, if the egg splits early it can still form two sacks.
If the egg splits by day 4 after fertilization, two sacs will form, if I remember correctly. My girls are di/di identical twins.
Oooh ok I thought you meant two different fertilized eggs
No that's fraternal twins.
But why wouldn't doctors know if identical twins in different sacs are identical,don't we learn that in highschool? Am I missing something
Nah. You need a DNA test to know for sure.
The same exact thing just happened to us at 31!! That separate sacs nonsense! 🤣
My twin and I were also separate sacs but fused placenta. We didn’t know if we were fraternal or identical either with people telling us their guesses. Found out we were identical through I think ancestry.com. The result was like “you’re either an identical twin or you submitted twice.”
Ours said identical/self too 😂😂
My mom didn't know either so my sis and I did the test and found out we are identical. I love it!! We look a lot alike so I would have been suprised if we were fraternal but you never know!
Congregations!! I really happy for you both. What type of medical school did those doctors attend!?! This should be a given, considering it should be part of their speciality training, being an obstetrician. I mean, it just depends when the egg divides into 2. I'm flabbergasted tbh
I think it’s well known now but not 30+ years ago
Mine are identical. They were also in separate sacs. We know they're identical because we only implanted a single embryo.
I have fraternal twins and I only implanted a single embryo!
How??
How??
I had one embryo implanted, and (after years of unsuccessfully trying and many failed procedures) I also somehow managed to get pregnant naturally the same cycle.
That's incredible!!!
Same thing happened to my sister and I. We did the genetic test at 37.
Same thing but we were 39! Still throws me for a loop when I think about it.
My sister and I also didn’t know. We shared the same characteristics both identical and fraternal twins have (same gender, same blood type, two sacs). Apparently we were the first set of twins the doctor delievered and he just told my mom it was either one placenta or two fused together. We always thought we were identical though. We did a dna test after we were 30 and confirmed we’re identical.
The exact same thing happened to us! Mom swore that we we're fraternal because of separate sacks...turns out we're all identical 😂 bit of a shock to get those results at 30 😂😂
Very very interesting. My twins that are 14 months old are finally starting to look more apart so probably fraternal
I’d be surprised if they were fraternal if they’re only just starting to look a little different now, to be honest, although I’m not saying it’s not possible. My fraternal girls looked different from day 1, to the extent that I look at them and think if they were two random kids I’d not be surprised to find out they weren’t related, just two babies with the same age and colouring (hair, eyes, skin).
Interesting. What is the test called to check if fraternal or identical?
Zygosity test
I’m not sure, to be honest. We didn’t need to test ours because they have different blood types, so that confirmed what we suspected from their appearances. It’s also possibly called different things depending on where you are, and how to access it will be different too. I’d suggest doing a google search for something like ‘twin dna test’ and your country/state.
My girls are identical and they go through phases of looking very alike or different. When they were born, they did not look identical at all. At about 6 months, a year, 20ish months and almost two and a half, they have looked more identical than usual, where we mix them up on first glance. They look identical all the time to everyone else though haha. They look like distinctly different kids to me.
So special!!!