If you mean, who is his wife, then the answer is Michelle Obama.
If the question is really asking about a "waif" of President Obama, since waif is often used to mean: "a person, especially a child, who has no home or friends", then the answer would have to be that he does not have one to our knowledge.
Abraham Lincoln
1100
47.
President Obama doesn't have a son.
Michelle Obama
Senator.
Joe Biden
He is President-Elect Obamas senior advisor.
Ann Dunham
The president and his family do not have a cat; they have a dog, whose name is Bo.
The waif looked at him with large eyes. The waif was undernourished. The waif was one of many homeless children.
A waif can be either a male or female. A waif is a homeless person and is usually used in reference to a child. Synonyms for the word waif are urchin and ragamuffin.