The current situation is either an American mother or an American father can impart citizenship to a child born abroad provided they have spent a sufficient time (five years I think) after their 14th birthday in the United States.
This was not always the case. Prior to the Cable act of 1922, only fathers could impart citizenship to children born abroad.
DiogenesLamp is correct. Here’s the section of current law on who qualifies as a “Citizen of the United States At Birth,” if born abroad:
“a person born outside the geographical limits of the United States and its outlying possessions of parents one of whom is an alien, and the other a citizen of the United States who, prior to the birth of such person, was physically present in the United States or its outlying possessions for a period or periods totaling not less than five years, at least two of which were after attaining the age of fourteen years”—8 U.S.C. § 1401
If what you say is true, then I don’t know what all the fuss about Obama’s citizenship is except people not liking him or his views.