How Common are Boy/girl Twins?

[miyavicandy]

I'm pregnant with twins and dont know if fraternal or identical yet. doc couldnt tell. but im hoping for boy/girl twins. how common are they? like are fraternal's most likely boy girl? or could be boy boy or girl girl. what is more common when having fraternal twins?

 

[MommyGrim]

It'd have the same likelihood as someone having a girl singleton pregnancy then having a boy singleton sometime later, I'd imagine.

 

[Meezerowner]

If you could know that they were *defo* frats then it would be:
BB=1/4
BG=1/4
GB=1/4
GG=1/4

Therefore 1/2 chance of one of each.

Unfortunately even if the are found to be DCDA there is noway of guaranteeing that they are fraternal as a small amount of early splitting ID's are also DCDA.

All IDs are same gender (there is a *very* rare exception that can be ignored for the sake of arguement). So as we cant know what type of twinning you have going on in there your chances are reduced to about 1/3 (ish). That's why it seems as if there are less boy/girl combos out there.

If at your next scan they determine that you have IDs then there is no chance of one of each I'm afraid ...... except in the extremely rare exception (it is possible for a set of ID boys to become one of each if one of the boys loses his Y chromosome due to a genetic hicup after splitting. If this happens you do get one of each but the girl will only have one X chromosome and therefore have Turner's syndrome).

 

[5drops]

Do they run in your family? Then maybe you will. I hope most importantly they are healthy.