It is just my personal opinion, but I believe that natural born citizenship is derived when both parents are citizens at the time of birth. Not wanting to start any war here, but because of that understanding, I do not believe that Ted Cruz is eligible to be president.
On the other hand, I also believe that Barack Obama was not constitutionally qualified to be president. If I belief that Obama was not qualified, I can not then declare Cruz to be qualified and be intellectually honest.
Now, if the Supreme Court were to decide that constitutional question, one way or another, then I would be satisfied. Or if congress were to draft laws determining what constitutes a natural born citizen, then I again, would be satisfied.
Once again, I say this is my personal opinion based upon my simple reading of the constitution. If other parties disagree, so be it.
The Supreme Court did already decide how to define Natural-born Citizen in Minor v. Happersett. That definition was affirmed in U.S. v. Wong Kim Ark and the Minor precedent on presidential eligibility was affirmed in Luria v. United States. IOW, 27 Supreme Court justices agreed with Minor that NBC is defined as all children born in the country to citizen parents. Those born outside the country and born to an alien father can only become citizens through the naturalization authority of Congress.