Oedipus had four children with his wife, Jocasta—who was also, of course, his mother. Oedipus had no idea that the woman he married had also given birth to him so many years before. Oedipus's parents were not at all anticipating the idea that their son would arrive and interfere with their later lives, since they had set aside the prophesy that he would kill his father and marry his mother. Oedipus, marrying his own mother Jocasta, produced four children: two girls, Antigone and Ismene; and two boys, Polynices and Eteocles.
The birth of these children was understood to fulfill the prophecy that had been expressed about the town. Many years after Oedipus's were born, others in the town fell prey to infidelity and became concerned about their own potential to bear children.
I'm assuming that you're asking about the children of the mythical king of Thebes, Oedipus, who is the subject of Sophocles' three Theban plays. Oedipus, who was given up at birth by his father, Laius, the then King of Thebes, because it was prophesied that his child would kill him, unwittingly fulfills the prophecy by killing his birth father and marrying his mother, Jocasta, with whom he has four children — Antigone, Ismene, Eteocles, and Polynices. The first two are girls the second two are boys. They are, of course, also his half-siblings although he doesn't learn this until much later. A fight between Eteocles and Polynices later results in a civil war. Antigone is later buried alive by King Creon.