Makes no difference. Rubio was born here ergo he is a US citizen. If not, then I must have been a citizen of Canada all these years and didn't know about it since my father was a Canadian citizen until I was about 5 years old. Andrew Jackson? Guess what. His parents were born in another country. Ditto even George Washington.
Try doing some reading....
http://bobmccarty.com/2011/04/22/revisiting-the-obama-eligibility-question/