Take the 2-minute tour ×
Mi Yodeya is a question and answer site for those who base their lives on Jewish law and tradition and anyone interested in learning more. It's 100% free, no registration required.

Specifically what kind of relationships are defined as incestuous in Judaism? I am guessing that it is forbidden to marry one's parents/children or siblings but what about other relations like first cousins?

Also, what is the specific source (is this outlined Biblically or rabbinically)?

share|improve this question
See Leviticus 18 and 20 –  Double AA Jul 23 '13 at 21:27
Cousins could get married, but today it's kind of gross. –  A L Jul 24 '13 at 3:44
@AL Why is it gross? –  Fixed Point Jul 24 '13 at 5:49
Fixed Point, welcome to Mi Yodeya, by which I hope you're attracted, rather than repelled. –  msh210 Jul 24 '13 at 6:20
Let me echo @msh210's welcome and add that I hope you'll look around the site and find other material you can relate to, perhaps including our 180 other marriage questions. –  Isaac Moses Jul 24 '13 at 11:39

1 Answer 1

up vote 9 down vote accepted
  • Mother (B)
  • Mother's mother (R)
  • Mother's mother's... mother (R)
  • Mother's father's mother (R)
  • Father's mother (R)
  • Father's mother's... mother (R)
  • Father's father's mother (R)
  • Father's wife (B)
  • Father's father's wife (R)
  • Father's father's... father's wife (R)
  • Mother's father's wife (R)
  • Father's mother's father's wife (R; some permit)
  • Father's paternal brother's wife (B)
  • Father's maternal brother's wife (R)
  • Mother's brother's wife (R)
  • Sister (B)
  • Non-Jewish sister (R; some permit)
  • Daughter (B)
  • Daughter's daughter (B)
  • Son's daughter (B)
  • All further female direct descendants (R; some permit)
  • Wife's daughter (B)
  • Wife's daughter's daughter (B)
  • Wife's son's daughter (B)
  • All of wife's further female direct descendants (R; some permit)
  • Wife's mother (B)
  • Wife's mother's mother (B)
  • Wife's father's mother (B)
  • All of wife's further female direct ancestors (R; some permit)
  • Father's sister (B)
  • Mother's sister (B)
  • Son's wife (B)
  • Son's son's wife (R)
  • Son's son's... son's wife (R)
  • Daughter's son's wife (R)
  • Brother's wife (B)
  • Wife's sister while wife is alive (B)

(B = biblically prohibited, R = rabbinically prohibited)

Source: Shulchan Aruch Even HaEzer 15

share|improve this answer
Great answer (and +1), but you might want to add that one's niece is not a forbidden relationship - and was traditionally considered a good match. You didn't say that it was prohibited, but someone scanning the list might fail to notice that it's not mentioned. –  Shimon bM Jul 24 '13 at 8:35
do the ellipses mean that it doesn't matter how many generations? –  Menachem Jul 24 '13 at 12:52
@Menachem Yes.​​​​​​​​​​​​​​ –  Double AA Jul 24 '13 at 13:10

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.