National geographic channel--b/g identical?

did anyone else see this?... NGC had a show on that showed the development of multiples it was in 3 and 4-d ultrasounds, and they explained that rarely b/g can be identical because they spilt with "xxy" chomosones and then when seperate they each drop the extra one sometimes one drops the y and the other drops an x

 

did anyone else see this?... NGC had a show on that showed the development of multiples it was in 3 and 4-d ultrasounds, and they explained that rarely b/g can be identical because they spilt with "xxy" chomosones and then when seperate they each drop the extra one sometimes one drops the y and the other drops an x

 

I think it's really rare and usually results in the female having a disorder.

 

Strange. Never heard of that. Doesn't sound natural though.

 

I saw that show! It was so fascinating. I didn't know that! I always thought identicals were the same sex. It was really interesting. Mary

 

Yeah I saw that special. Found it totally fascinating, as I saw the babies pushing on each other and hitting it reminded me of our ultrasounds. We watched so many times a hand or foot come out of nowhere and slap or kick their sister. Back to the subject of b/g ID I thought it was fascinating but wondered if they had any disorders from it. I totally didnt know that it could happen.

 

There was a discussion about this on PC and one of the gals weighing in is a geneticist. You might want to find the thread.

Anyway, I believe the conclusion was that it's a theory with no documented cases and the show did a poor job of explaining this. There are, however, documented cases of monozygotic twins where one twin is XY and the other just an X so one is a normal boy and the other a girl with Turner's Syndrome. They are monozygotic but NOT identical because the genome no longer matches.

 

We had a really big discussion about this when it first came out..if you click on my profile you should be able to dig it up... I started the thread... The basic conclusion that we came to is that this is extremely rare... when it does happen the result is usually a normal boy and a girl who has male dna but has the external organs of a female...turner's syndrome..she is sterile and I believe has no organs such as a uterus, etc... essentially she was meant to be a boy, but somehow lost her Y chromosome..there's a huge array of other health problems these kids face and many do not survive long...

There is the theoretical possibility of producing HEALTHY "identical" boy/girl twins... you'd have to read through all the posts on the thread I referred to to fully comprehend the theory behind it... but essentially we were unable to find a single documented case where it had actually happened... so as far as I know it's only theoretical and NGC was really irresponsible for presenting their b/g identical twins with the picture of a healthy normal set of b/g fraternal twins... It's theoretical to have a healthy set and for the very rare case where you do have b/g identical twins there are so many health problems that NGC should have emphasized that rather than glossing over the subject...or perhaps they should have left the possibility out entirely since they didn't have time to discuss it properly. JMHO... it caused nothing but confusion for those unaware of this rare occurance..and pain for those few who have been touched by it..as if their b/g identicals are perfectly healthy... or as if any fraternal b/g twins who happen to look very similar are really identical b/g twins... they just added a lot of confusion to the issue of fraternal vs. identical.. the possibilities are so slim that you are pretty safe in assuming that if you see a pair of b/g twins that they are indeed FRATERNAL... anyway to see my processed out rant on this, just dig in my profile from a few weeks back...