I have a boy/girl pair but neither has a claim to the 2E label. However. DS, who may be the brighter twin, actually have had some 2E type symptoms. At age 6, when he was already able to read Harry Potter both fluently and independently, he still had some problems with letter orientation (b versus d, p versus q, etc.). It boggled my mind that he was able to speed read with great comprehension while having such difficulties. That slowy got better and I don't think he has that problem anymore. However, he still struggles with differentiating between left and right despite extensive and persistent efforts to help him compensate. His handwriting is horrible but the OT who assessed him felt that it was due to his greater mental ability and his speed.
I have this theory that there may be more 2E twins due to prematurity and low birth weight and more difficult prenatal environments (sharing, crowding, etc.). It also appears that naturally conceived twins have lower incidence of problems. My twins were conceived naturally and delivered without surgical intervention at 38 weeks so not exactly typical. I don't remember the stats now but most multiple births are the result of artificial insemination and other procedures due to infertility, which is why mulitple births are so common now as compare to 30 years ago.
