Did it? The last major change to immigration law prior to Obama's birth was the Immigration and Naturalization Act of 1952. Title III, Chapter 1, Article 301, paragraph g stated that "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..." was a natural born citizen. If the law was change to residing in the U.S for at least ten years, at least five of which had to be after the age of 16 then when did this change take place?
INA of 1952. Link at the bottom takes you to the act itself.
Of course, if he was born in the United States, this does not even apply to him, he already has birthright citizenship, the same as anyone else born in the U.S.. This law would only apply if he had been born outside the U.S.
The 1994 law:
a. As amended by Public Law 103-416 on October 25, 1994, section 301 states as follows with respect to persons born abroad:
b. Sec. 301. The following shall be nationals and citizens of the United States at birth:
...
g. 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: Provided, That any periods of honorable service in the Armed Forces of the United States, or periods of employment with the United States Government or with an international organization as that term is defined in section 1 of the International Organizations Immunities Act (59 Stat. 669; 22 U.S.C. 288) by such citizen parent, or any periods during which such citizen parent is physically present abroad as the dependent unmarried son or daughter and a member of the household of a person (A) honorably serving with the Armed Forces of the United States, or (B) employed by the United States Government or an international organization as defined in section 1 of the International Organizations Immunities Act, may be included in order to satisfy the physical-presence requirement of this paragraph. This proviso shall be applicable to persons born on or after December 24, 1952, to the same extent as if it had become effective in its present form on that date;
Note that this condition applies retroactively to Obama, as the following condition shows:
l. RETROACTIVE APPLICATION:
(1) Except as provided in paragraph (2), the immigration and nationality laws of the United States shall be applied (to persons born before, on, or after the date of the enactment of this Act) as though the amendment made by subsection (a), and subsection (b), had been in effect as of the date of their birth, except that the retroactive application of the amendment and that subsection shall not affect the validity of citizenship of anyone who has obtained citizenship under section 1993 of the Revised Statutes (as in effect before the enactment of the Act of May 24, 1934 (48 Stat. 797)).
(2) The retroactive application of the amendment made by subsection (a), and subsection (b), shall not confer citizenship on, or affect the validity of any denaturalization, deportation or exclusion action against, any person who is or was excludable from the United States under section 212(a)(3)(E) of the Immigration and Nationality Act (8 U.S.C. 1182 (a)(3)(E)) (or predecessor provision) or who was excluded from, or who would not have been eligible for admission to, the United States under the Displaced Persons 1948 or under section 14 of the Refugee Relief Act of 1953.
This information comes from pp. 15-17 of the following U.S. State Department document:
7 FAM 1130
ACQUISITION OF U.S. CITIZENSHIP BY
BIRTH ABROAD TO U.S. CITIZEN PARENT
which is available in PDF format here:
http://www.state.gov/documents/organization/86757.pdf
I hope this makes the matter clear.