Can identical twins be one boy and ony girl?

Hello, everyone,
I am now 16 weeks pregnant and will find out the sex of the babies
next Thursday. My husband and I were told that the identical twins
will be either all boys or girls from the beginning so I thought that identical twins are always the same sex. But we watched a twin program on Sunday and they mentioned on TV that the couple's identical twins are one boy and one girl. I am really confused now and haven't read any books about wether they can be different sex or not.

Does someone know more about this? Please advise.

Oh, by the way, a special twin program will be on Jan 14 at 8 P.M.
on National Geographic channel...It will be an awesome twin
educational program for all of the twin moms...Don't forget
to watch it!!! I cannot wait.

Thanks,
Esha

 

Hello, everyone,
I am now 16 weeks pregnant and will find out the sex of the babies
next Thursday. My husband and I were told that the identical twins
will be either all boys or girls from the beginning so I thought that identical twins are always the same sex. But we watched a twin program on Sunday and they mentioned on TV that the couple's identical twins are one boy and one girl. I am really confused now and haven't read any books about wether they can be different sex or not.

Does someone know more about this? Please advise.

Oh, by the way, a special twin program will be on Jan 14 at 8 P.M.
on National Geographic channel...It will be an awesome twin
educational program for all of the twin moms...Don't forget
to watch it!!! I cannot wait.

Thanks,
Esha

 

No, it is genetically impossible for identical twins to be one girl and one boy. That would mean they would have different sex chromosomes and therefore could not be identical. Identical twins are always the same genetic makeup.

The only thing I could possibly think of is some rare case where one twin did not develop their sexual organs in a normal manner, and they were at first mistaken for being two seperate genders. But still their genetic makeup would be the same.

Good luck,

Mellie
DD 2 years old
33 weeks b/g twins!

 

I don't know the odds, but yes, it can happen. I don't know the details or how to explain it well...but basically an egg is fertilized but there is a genetic abnormality to it. The egg splits, creating identical twins. Because of the abnormality, one of the twins presents as the opposite gender. Identical twins genetically.

There is a woman on here who has experienced it. She had a set of identical twins that presented as one male & one female. They confirmed they were identical twins genetically after birth. The female had male DNA but physically appeared female. Sadly, she only lived minutes after birth. The boy twin is doing well.

 

Though I have heard that it can happen, it is such a complete freak and rare thing that you can safely bet your money that if your twins are identical, they are the same sex.

 

It is possible, but rare. Bth parents would have to have an extra chromosome. And both parents would pass on 2 chromosomes elliminating the X or Y that happens to be extra at just the right time. It is possible but rare. This would take place outside the nucleus of the cell in the mytochondria.

 

Wow, you learn something new every day! I thought the answer to this question would be an absolute no.

 

I think the wording is a little difficult though. Identical twins can't be one boy one girl but monozygotic twins can be one boy one girl. Unfortunately, monozygotic has grown to mean identical for many people thus the confusion.

 

Yes, "identical" twins can be one boy and one girl, but the odds of that happening are very very very low (I think there are only 2-3 living sets of ID b/g twins in the world) and the "girl" (which is actually a boy that lost his Y chromosone) is very sickly. It's a genetic disease.

Your twins are most likely either boys or girls, but yes, it is possible, very very rare, but possible.

 

The missing Y chromosome creates a condition in the female known as Turner's syndrome. That's the only way it can happen...

 

quote:
Originally posted by Renald99:
I don't know the odds, but yes, it can happen. I don't know the details or how to explain it well...but basically an egg is fertilized but there is a genetic abnormality to it. The egg splits, creating identical twins. Because of the abnormality, one of the twins presents as the opposite gender. Identical twins genetically.

There is a woman on here who has experienced it. She had a set of identical twins that presented as one male & one female. They confirmed they were identical twins genetically after birth. The female had male DNA but physically appeared female. Sadly, she only lived minutes after birth. The boy twin is doing well.


I am that woman she is talking about. And yes in our case this is what happened. Lilly in fact has male DNA, she passed away after birth. Later we found out it was due to IUGR, TTTS & a few other things. It is VERY rare, but it does happen. We are living proof of it. If anyone has any questions, please feel free to PT me, I am finally getting to that point in my grief where I am willing to talk about.

 

Hi, Thanks for all of your replies to this question.

I will wait until my doctor's appt to find out what I am having!!!

Shelly, I am so sorry to hear about Lilly. I love that name!

I don't feel nervious about it at this point and just hope
that they both are girls or boys.....

I will keep you updated next week.

Thanks!
Esha

 

Shelly-I'm glad you saw this thread as you are the one that can answer the question best. I hope you don't mind I referenced your story (and I hope I didn't explain it poorly...couldn't find more info on TS or online to explain it). How very nice of you to offer to answer peoples questions about the subject. I didn't realize Carter & Lilly were also facing IUGR & TTTS. How amazing that she was able to hang on long enough to save her brother and how incredible that he beat those odds and being a preemie. Amazing.



ps. The kids are adorable in their jerseys!

 

no