Charles Ellicott Commentary 1 Kings 11:20

"And the sister of Tahpenes bare him Genubath his son, whom Tahpenes weaned in Pharaoh`s house; and Genubath was in Pharaoh`s house among the sons of Pharaoh." — 1 Kings 11:20 (ASV)

Genubath is similarly unknown. The weaning in the house of Pharaoh, no doubt with the customary festival , indicated the admittance of the child into the royal family of Egypt.