Later, she conceived again, bore another son, and named him Onan.

So Judah instructed Onan, "You are to have sexual relations with your dead brother's wife, performing the duty of a brother-in-law with her, and have offspring for your brother."

But Onan knew that the offspring wouldn't be his own heir, so whenever he had sexual relations with his brother's wife, he would spill his semen on the ground to avoid fathering offspring for his brother.

The LORD considered what Onan was doing to be evil, so he put him to death, too.

and Judah's sons Er, Onan, Shelah, Perez, and Zerah. (Technically, Er and Onan had died in the land of Canaan.) Perez's sons were Hezron and Hamul.

The descendants of Judah originally included Er and Onan, though Er and Onan died in the land of Canaan.

Judah's three sons Er, Onan, and Shelah were born to him through Bath-shua, a Canaanite. Er, Judah's firstborn, became wicked in the LORD's sight, so he put him to death.