Genesis 30:4

30:4 So Rachel ¹  gave him her servant Bilhah as a wife, and Jacob had marital relations with ²  her.

Genesis 30:9

30:9 When Leah saw that she had stopped having children, she gave ³  her servant Zilpah to Jacob as a wife.

Genesis 35:22

35:22 While Israel was living in that land, Reuben had sexual relations with ⁴  Bilhah, his father’s concubine, and Israel heard about it.

Jacob had twelve sons:

Genesis 35:25-26

35:25 The sons of Bilhah, Rachel’s servant, were Dan and Naphtali.

35:26 The sons of Zilpah, Leah’s servant, were Gad and Asher.

These were the sons of Jacob who were born to him in Paddan Aram.

[30:4]  ¹ tn Heb “and she”; the referent (Rachel) has been specified in the translation for clarity.

[30:4]  ² tn Heb “went in to.” The expression “went in to” in this context refers to sexual intercourse.

[30:9]  ³ tn Heb “she took her servant Zilpah and gave her.” The verbs “took” and “gave” are treated as a hendiadys in the translation: “she gave.”

[35:22]  ⁴ tn Heb “and Reuben went and lay with.” The expression “lay with” is a euphemism for having sexual intercourse.