Genesis 38:2-6

Judah saw there a daughter of a certain Canaanite whose name was Shua; and he took her as a wife and had relations with her.

And she conceived and gave birth to a son, and he named him Er.

Then she conceived again and gave birth to a son, and she named him Onan.

She gave birth to yet another son and named him Shelah; and it was at Chezib that she gave birth to him.

Now Judah took a wife for Er his firstborn, and her name was Tamar.