But that's not a law!
A. Yes, it is the law. Your definition of law is wrong. Judicial and Administrative law is still law.
Regarding the caller on the Alex Jones show claiming that both parents must be U.S. citizens:
"Article II, Section 1, Clause 5 of the Constitution sets the principal qualifications one must meet to be eligible to the office of president. A president must: be a natural-born citizen of the United States;" -- http://en.wikipedia.org/wiki/President_of_the_United_States
"The Constitution does not define the phrase natural-born citizen...