IIRC, there’s a requirement that, if a child is born out of the country to parents only one of which is an American citizen...that citizen, in this case the mother, had to reside within the area of the U.S. proper for a period of 5 years after her 16th birthday. Since Obama’s mother was 18 at the time of his birth, she nor he would not qualify if he was born in Kenya.
Thank you. That makes sense. I had been wondering about this for a while.