Obama has half-siblings from his father’s first and third marriages in Africa .
Malik Obama (half-brother ) (b 1958)
Auma Obama (half-sister b 1960)
Abo Obama (maybe adopted half-brother b 1968)
Bernard Obama (maybe adopted half-brother b 1970)
Mark Ndesandjo ) half-brother by father’s third wife b c.1965
David Ndesandjo (1967-1987) half-brother by father’s third wife,
George Hussein Onyango Obama ( illegitimate half-brother, b c 1982)
http://wiki.answers.com/Q/Who_are_Barack_Obama’s_siblings