Marco Rubio is a citizen because he was born in the U.S.A.
But he is not now, nor will he ever be, a natural born Citizen.
Three types of citizenship are recognized by our government: native born; naturalized; and citizen-by-statute (derived citizenship from parents). All have equal rights. All can serve in Congress, either as a Representative in the House, or as a Senator in the Senate.
The following link will take you to the governments own Immigration Service web page describing the three types of citizenship.
Natural born Citizen is NOT a type of statutory citizenship. Natural born is ONLY an eligibility requirement for the U.S. Presidency per Article II, Section 1, clause 5, of the U.S. Constitution, and requires, as per the Founders, the President to be born in the United States (jus solis) AND of two citizen parents (jus sanguinas).
The definition of natural born Citizen appears in the holding of SCOTUSs unanimous decision of Minor v. Happersett (1874).
Virginia Minor sued to be included as a candidate for U.S. President based on her eligibility under the 14th Amendment to the U.S.Constitution.
SCOTUS rejected her argument and examined her eligibility, concluding that she belonged to the class of citizens who, being born in the U.S. of citizen parents, was a natural born Citizen, and not covered by the 14th Amendment.
This holding has been used in 25 consequent SCOTUS decisions since 1875.
No one has the RIGHT to be President.
The eligibility requirement of Natural Born Citizenship (jus solis + jus sanguinas: born in the U.S. of U.S. citizen parents) must be viewed as a means to prevent split allegiance for any President of the United States.
But the Minor V. Happersett case originally had absoutely no relevance whatsoever to presidential eligibility. Ms. Minor was not seeking the office of President when she filed her suit, far from it. (At the time, it would have been an earth-shaking event if a woman was seeking the presidency; this case was decided in the late 1800s, decades before the passage of the Nineteenth Amendment, guaranteeing a woman's right to vote in all states.) Minor v. Happersett frequently comes up in the debate over constitutional qualifications for the presidency merely because in discussing citizenship in its ruling, the Court went off on a bit of tangent and explained the definitions of various types of citizenship, including natural born citizenship. That definition from the SCOTUS in the Minor case was in accord with the definition of "natural born citizen" expounded by Vattel c. 1770, which is the source used by the framers of the Constitution when they inserted the phrase into the document as a qualification required for the President.