WASHINGTON — Sen. Marco Rubio believes gays and lesbians are born that way — but they don’t have a fundamental right to marry.

Marriage should be between one man and one woman, but states that disagree should be allowed to make their own rules, Rubio said on CBS’s “Face the Nation” on Sunday.

“It’s not that I’m against gay marriage,” said Rubio (R-Fla.). “I believe the definition of the institution of marriage should be between one man and one woman. States have always regulated marriage. And if a state wants to have a different definition, you should petition the state legislature and have a political debate.”

“I don’t believe same-sex marriage is a constitutional right. I also don’t believe that your sexual preferences are a choice for the vast and enormous majority of people. In fact — the bottom line is that — you know, I believe that sexual preference is something that people are born with,” he continued.

Now 37 states allow marriage for gay couples, but the Supreme Court is poised to decide the civil rights issue nationally when justices hear oral arguments this month on whether states can ban same-sex couples from marrying.

Last June, Democratic presidential candidate Hillary Clinton told NPR she supports the expansion of same-sex marriage undertaken by activists on a “state-by-state” basis. But last week, she shifted her position in favor a Supreme Court ruling to legalize same-sex marriage nationally.

“Hillary Clinton supports marriage equality and hopes the Supreme Court will come down on the side of same-sex couples being guaranteed that constitutional right,” spokeswoman Adrienne Elrod said Wednesday.

To emphasize the point, Clinton featured same-sex couples in her campaign launch video, including one gay couple planning to wed.

Rubio is the third Republican to jump into the presidential contest, after Sens. Ted Cruz of Texas and Rand Paul of Kentucky. His comments that sexual orientation is not a choice is a departure in GOP politics, where some social conservatives argue that being gay is a lifestyle choice and morally sinful.

Democrats have shifted quicker on the issue of same-sex marriage. President Obama, who once backed civil unions and not marriage, just this month called for an end to “conversion” therapies for minors after the suicide of a 17-year-old transgendered youth who received religious reparative treatment.