A most perplexing question was posed to me today, curious to see others thoughts --
A baby girl is adopted after the first day of birth. The adoptive parents are a frum couple who are told the baby's mother is Jewish by reputable sources. They are full believers in the truth of this information.
They raise their daughter, Beis Yaakov, seminary in Yerushalayim, marries a Cohen, and b"h, eventually two baby boys. Both undergo bris according to Halakah.
The woman's boys too grow up, go to yeshiva, receive simcha, chuppa, kollel, and have children of their own.
As the years pass their mother begins looking for her birth parents, only to find out to her astonishment, after years and years of searching, that her birth mother was indeed, not Jewish.
What is her halakhic standing? That of her sons? What is their standing? That of their Kohan status? Their smichas? Their own children? Must a conversion to be done to all three generations? Must a bris be redone? Do any other problems arise in your minds? Remedies?
Keep in mind that we are discussing frum families (shomrei mitzvos) according to Halakha, answered pertaining to Reform or Conservative laws are not relevant to the question.