During an appearance on CBS' "Face The Nation," Rubio, who launched his 2016 presidential campaign last week, said that he believes the definition of marriage is a union between a man and a woman. The Florida senator also added said that same-sex marriage was not a constitutional right and should be decided by state legislatures, not the courts.

Despite his position, Rubio added that he didn't think being gay was a choice.

"I also don't believe that your sexual preferences are a choice for the vast and enormous majority of people," he said. "In fact, the bottom line is I believe sexual preference is something that people are born with."

Last week, Rubio also said that he would attend a gay wedding of a loved one, even if he disagreed with the "choice" that loved one had made.

“I’m not going to hurt them simply because I disagree with a choice they’ve made or because I disagree with a decision they’ve made, or whatever it may be,” Rubio said. “Ultimately, if someone that you care for and is part of your family has decided to move in one direction or another or feels that way because of who they love, you respect that because you love them.”

In the past, Rubio has distinguished between opposing same-sex marriage and being anti-gay.

"Supporting the definition of marriage as one man and one woman is not anti-gay. It is pro-traditional marriage," Rubiosaid last year.