Which kind of relations are considered incestuous in Judaism?

Question

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)?

Answer 1

• 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