Thank you. That helps a lot. If I understand your position correctly there are two possibilities. The first is that only one of the fertilized eggs had a soul, and the other possibility is that her soul came to the two eggs when they joined.
I will accept your answer, but I must point out that both possibilities that you give say that not every fertilized egg has a soul and this may bear on the issue of the morality of abortion.
By the way, this woman is not actually unique. There are a total of three people who have been found to be like this, and it is generally agreed that the condition is drastically underdiagnosed. Inorder to find people like this, multiple tests have to be done of different organ systems to find differences. This particular woman was found only because she needed a kidney transplant and the initial tests said that two of her children were not her children. Tests of other organs of her body matched the two children under question.
