Mishnah Niddah 4:1: The daughters of Samaritans are [considered to be] niddot [females who have menstrual discharges which render them impure] from their cradle. And Samaritans render impure that which they lie upon, [rendering] the bottom one [impure, even without touching it,] just as the top one, since they have intercourse with niddot, and they [their wives] sit [counting seven days of impurity] on account of any [kind of] blood [even blood which does render them impure, which thereby throws off their count]. But one is not liable for entering the Temple [while impure] on account of [having been rendered impure or carrying something which has been rendered impure by] them, nor is terumah [a portion of a crop given to the priests which can only be consumed by priests or their household, and which one is forbidden to render impure or consume while impure] burned on their account [if rendered impure by them], because their impurity is uncertain.

בְּנוֹת כּוּתִים, נִדּוֹת מֵעֲרִיסָתָן. וְהַכּוּתִים מְטַמְּאִים מִשְׁכָּב תַּחְתּוֹן כָּעֶלְיוֹן, מִפְּנֵי שֶׁהֵן בּוֹעֲלֵי נִדּוֹת, וְהֵן יוֹשְׁבוֹת עַל כָּל דָּם וָדָם. וְאֵין חַיָּבִין עָלֶיהָ עַל בִּיאַת מִקְדָּשׁ, וְאֵין שׂוֹרְפִין עֲלֵיהֶם אֶת הַתְּרוּמָה, מִפְּנֵי שֶׁטֻּמְאָתָן סָפֵק:

Mishnah Niddah 4:2: The daughters of Sadducees, so long as they are accustomed to walking in the paths of their fathers, are thereby [regarded] as Samaritan women. If they left [those paths] to walk in the paths of Israel, they are thereby as Israelites. Rabbi Yose says: they are always like Israelites, until they leave [that path] to walk in the paths of their fathers.

בְּנוֹת צְדוֹקִין, בִּזְמַן שֶׁנָּהֲגוּ לָלֶכֶת בְּדַרְכֵי אֲבוֹתֵיהֶן, הֲרֵי הֵן כְּכוּתִיּוֹת. פֵּרְשׁוּ לָלֶכֶת בְּדַרְכֵי יִשְׂרָאֵל, הֲרֵי הֵן כְּיִשְׂרְאֵלִית. רַבִּי יוֹסֵי אוֹמֵר, לְעוֹלָם הֵן כְּיִשְׂרָאֵל, עַד שֶׁיִּפְרְשׁוּ לָלֶכֶת בְּדַרְכֵי אֲבוֹתֵיהֶן: