Genesis 16:2 So Sarai said to Abram, "Now behold, the LORD has prevented me from bearing children. Please go in to my maid; perhaps I will obtain children through her." And Abram listened to the voice of Sarai.

Genesis 16:4 He went in to Hagar, and she conceived; and when she saw that she had conceived, her mistress was despised in her sight.

Genesis 38:8 Then Judah said to Onan, "Go in to your brother's wife, and perform your duty as a brother-in-law to her, and raise up offspring for your brother."

Deuteronomy 25:5 "When brothers live together and one of them dies and has no son, the wife of the deceased shall not be married outside the family to a strange man. Her husband's brother shall go in to her and take her to himself as wife and perform the duty of a husband's brother to her. (NASB ©1995)