However, take a note at this.
andLike all the Jedi of the old order, Kenobi was taken from his family as an infant to undergo training. He knew very little of his parents or of his brother, though he would later visit them on occasion
(EU section on starwars.com databank, for Obiwan and Owen Lars respectively)The only life Owen knew was that of moisture farming on Tatooine. He barely remembered the planet of his birth, Ator, or his mother Aika, who died when he was very, very young. He grew up on Tatooine, and his father, Cliegg, taught him discipline and the importance of family and responsibility. They were lessons that Owen took deeply to heart.
So, is it possible that Obiwan is still the brother of Owen Lars?