If it is a boy and a girl they can't be identical...they would be fraternal twins (with just a very strong familiar resemblance). Fraternal twins are two eggs, fertilized by two sperm. Identical twins come from one sperm, fertilizing one egg, that splits (making the offspring two identical beings).
Question for you, although I really should know this. Do identical twins share the same amniotic sac?
Off the subject just a hair, but did anyone see that Discovery program called "I Am My Own Twin" about the finding that a very few people apparently started out as fraternal twins in the womb, but one twin 'absorbed' the other and they have two totally separate sets of genes? I kid you not. It was the weirdest thing I have seen in awhile.
Thanks for clearing that up for me. For some reason I thought I heard her say that the boys would be identical...and how does she know it's a boy??