Mitt Romney said Thursday that same-sex couples should be allowed to adopt children, but they should not be married because children should be raised by a mother and a father.

Romney's appearance on Fox News wasn't the first time he made such a statement -- he has previously expressed his opposition to same-sex marriage and support for gay couples adopting -- but it held significance as his first national television interview after President Barack Obama thrust the issue into the campaign spotlight. The president said on Wednesday that he personally supports same-sex marriage.

Romney told Fox News' Neil Cavuto that his views on same-sex marriage are unchanged. He explained some of the rights he believes should be extended to gay couples. He said the issue is about what is best for the nation, referring specifically to children. He said his "preference" is that marriage continue to be defined as between a man and a woman.

"I happen to believe that the best setting for raising a child is where this is the opportunity to a mom and a dad to be in the home," Romney said. "I know there are many circumstances where that is not possible, through death or divorce. I also know many gay couples are able to adopt children. That's fine."

Cavuto asked him how he would respond to marriage equality supporters who say the issue is like the fight for civil rights.

"I don't really see it in that light," Romney said.

He attempted in the same interview to split hairs over whether he favors states' rights to define marriage or a constitutional amendment that would ban same-sex unions. Romney said he would support a constitutional amendment to define marriage as between a man and a woman -- effectively nullifying state decisions to legalize same-sex marriage -- but states could then decide on issues of benefits.

Romney said his family, as far as he knows, holds the same views on same-sex marriage. But he acknowledged that different people, including conservatives, hold different views on the matter, staying away from inflammatory rhetoric and reiterating that the opposition is his "belief."

"This is an issue which you cannot, really, convince someone about," he said. "It is something you either believe one way or the other."