A son is the male child of a mother and father. The opposite of a son is a daughter. If the child has siblings then the son is a brother.
Images for kids
King Chulalongkorn of Siam (far right) with a few of his 33 sons at Eton College in 1897
Miniature in Les Très Riches Heures du Duc de Berry depicting the Baptism of Jesus, where God the Father proclaimed Jesus to be his Son.