Yichud with a woman and her mother/daughter in-law:[1]

It is permitted to be in Yichud with a woman and her mother/daughter in-law.[2] [This refers to her husband’s mother, her son’s wife.[3] It is permitted to be in Yichud with such a pair even at night.[4] This allowance applies even if the man is accustomed to being around women and feels comfortable around them.[5] This allowance applies even if the man is well acquainted with the woman.[6] This allowance applies even if the man or woman is a Parutz [promiscuous man].[7] This allowance applies even if the two women share a great relationship.[8] This allowance applies even to live together on a permanent basis.[9] If the daughter in-law is no longer married to the woman’s son, such as due to death or divorce, Yichud is forbidden.[10] Likewise, a future daughter in-law who is not yet married, does not have this allowance apply.[11]]

• Practical examples: 1) It is permitted for a man to remain in the home of his friend even when his friend is out of town, if his friend’s wife and the wife’s mother in-law is at the home. 2) It is permitted by a Chupas Niddah for a Chasan and Kalah to remain together in their home if the Chasan’s mother is present. This applies even at night, when they go to sleep. 3) It is permitted for a man to stay alone by his grandmother’s home even if his aunt [Uncles wife] who is the daughter in-law of his grandmother is present.

_______________________________________________________________________________________

[1] Michaber 22/10; Kiddushin 81a; See Taharas Yisrael 22/23; Nitei Gavriel 24/1; The Laws of Yichud p. 60

[2] The reason: As these women hate each other and will never cover up for each other. [Michaber ibid]

[3] Zechor Leavraham 10; Implication of Parach Mateh Ahron 2/95; Pischeiy Teshuvah 22/11

[4] Taz 22/9; Rashal Kiddushin 4/24; Dvar Halacha 5/23-24; Poskim in Nitei Gavriel 24/16 footnote 26; The laws of Yichud ibid

Other opinions: Some Poskim rule that at night two Shomrim are required. [Beis Moshe 22/14, brought in Nitei Gavriel ibid]

[5] Beis Shmuel 22/14; Levush 22; Dvar Halacha 5/23-24

[6] Dvar Halacha 5/23-24

[7] Taharas Yisrael 22/23; Dvar Halacha 5/23-24; Tzitz Eliezer 6/40; However See Shevet Halevi 5/204

[8] Minchas Ish 11/28; Nitei Gavriel 24/10

[9] Perach Mateh Ahron 95; Dvar Halacha 5/23-24

[10] Dvar Halacha 5/22

[11] Nitei Gavriel 24 footnote 1