In Canada, to a Cuban father Oy vey!
And an American mother. Only takes one US citizen parent to pass on citizenship.
Now, Obama was born to a British citizen and a US underage girl (age of majority in 1961 was 21). Specific laws on the books at the time of his birth (under age, not living in US number of years required under the law), precluded his mother passing on her US citizenship to Obama.
Cruz was born to a US citizen mother, and a Cuban father. Under the law at that time his mother passed on her citizenship to Cruz. No naturalization needed.
You can argue Natural Born Citizen, but you cannot deny his is a US citizen, no matter how much you dislike him.