Can a woman be 1/1024 pregnant?
If it's all matrilinial then one is Jewish. If there's a break in the matrilinial line, then non Jewish. If a sofek, then dayonim might decide to do a giyur, depending on the circumstances.
Actually what
@neveryou said isn't so far fetched
I once heard a Vort from the Vilna Gaon, he asks why does it say that a Mamzer isn't allowed into Kehal Hashem "even the tenth generation".
He answers that a Mamzer is 1/2 Issur, his child is 1/4 Issur, 3rd gen is 1/8, 4th gen is 1/16, 5th gen is 1/32, 6th gen is 1/64, 7th gen is 1/128, 8th gen is 1/256, 9th gen gen is 1/512 and 10th gen is 1/1024 Issur, the Torah doesn't want you should think that Mamzeirus can be Botul in 1,000 so it says גם דור עשירי לא יבוא בקהל ה'.