Sotah 27A

דומה, ואל ישא בת דומה. שזו באה מטיפה כשרה, וזו באה מטיפה פסולה.

a woman whose suspected promiscuity is publicly spoken of [duma], and not marry the daughter of a woman suspected of promiscuity, as this woman, who is herself suspected of promiscuity, comes from seed of unflawed lineage; but that woman, the daughter of a woman suspected of promiscuity, comes from seed of flawed lineage, as she might be a mamzeret.

ורבי יוחנן אמר: ישא אדם בת דומה, ואל ישא דומה. שזו עומדת בחזקת כשרות, וזו אינה עומדת בחזקת כשרות.

And R' Yoḥanan says: It is better that a man marry the daughter of a woman suspected of promiscuity, and not marry a woman suspected of promiscuity, as this daughter maintains the presumptive status of virtuousness, but that woman suspected of promiscuity does not maintain the presumptive status of virtuousness.

מיתיבי: נושא אדם דומה! אמר רבא: ותסברא נושא לכתחלה?! אלא: אם נשא, תני נמי: ״בת דומה״.

The Talmud raises an objection to R' Yoḥanan’s statement from a baraita: A man may marry a woman suspected of promiscuity. Rava said in response: And how can you understand the baraita at face value? The baraita states that a man may marry her ab initio, yet clearly it is undesirable to do so. Rather, the wording of the baraita is imprecise, and one must render it: If one married a woman suspected of promiscuity, she is permitted to him. Since the baraita is imprecise, one should also correct it and teach: The daughter of a woman suspected of promiscuity.

והלכתא: ישא אדם בת דומה, ואל ישא דומה. דתני רב תחליפא בר מערבא קמיה דרבי אבהו: אשה מזנה ⁠— בניה כשרין, רוב בעילות אחר הבעל.

The Talmud concludes: And the halakha is that it is better that a man marry the daughter of a woman suspected of promiscuity, and not marry a woman suspected of promiscuity. This is as Rav Taḥalifa, from the West, i.e., Eretz Yisrael, taught before R' Abbahu: If a married woman engages in adulterous sex, her children are considered of unflawed lineage, as most instances of sex are attributed to the husband, and consequently it is presumed that the children were conceived by the husband and not by the paramour. Therefore, the daughter of a woman suspected of promiscuity is not suspected of being a mamzeret.