I'm watching "Multiples in the Womb" on the Discovery

[TheDebbieDee]

Channel and it is totally blowing my mind.

I just found out that identical twins (now called monozygotic twins) can be a boy/girl set of twins. It's a very interesting documentary with real footage of twins in the womb.

Check it out if you get the chance!

[CoffeeCat]

1. That's interesting...

I'm no doctor, but I always understood that monozigotic twins were from one
egg--and the result of that one egg splitting into two and developing into two
babies. Conversely, dizigotic twins are from 2 separate eggs released
from the ovaries.

I'm wondering how monozigotic twins could possibly be the opposite sex
since they are from one split egg.

I'd love to hear more!

[TheDebbieDee]

3. According to the documentary.........

the different-sexed identical twins result from the original, single cell having more than the usual number of sex chromosomes - that is, the original cell/zygote has xxxy chromosome instead of the usual xx or xy chromosomes.

When the cell splits into two babies, one baby gets xx chromosomes and the other baby gets xy chromosomes and thus you get monozygotic different-sexed twins!

[OPERATIONMINDCRIME]

2. Shit, I Forgot I Wanted To Record That. The Original 'In The Womb' Was Incredible.

Absolutely fascinating to watch that stuff. I hope it replays soon so I can tivo it.

[MiniMe]

4. Great documentary, but it is on National Geographic Channel, not Discovery

Minor thing, unless somebody is looking for it. :)

[Ilsa]

5. So I guess that idiotic question of boy-girl twins, "Are they identical"

isn't as stupid as it originally sounded.

[grace0418]

6. Cool, that explains the twins I knew in school (boy/girl). They were

identical in every way except for their sex. Very cool.