Former President George W. Bush's daughter called for gay marriage to be legalized — the latest sign that centrist and socially conservative Republicans might be divided over the issue.

Barbara Bush appeared in a short Human Rights Campaign video calling for "marriage equality."

"New York is about fairness and equality, and everyone should have the right to marry the person that they love," Bush says in the video, released by the gay-rights group on Tuesday.

New Hampshire and Iowa allow same-sex marriage, and in both states there is a drive by conservative groups such as the National Organization for Marriage (NOM) to restrict marriage to the union of one man and one woman.

NOM President Brian Brown recently told The Ballot Box that his group will pressure Republican presidential candidates on the issue.

"It won't just be, 'Do you agree with us?' " said Brown. "We don't want candidates who will just do lip service to marriage. We will have very specific policy positions that we hope the candidates will take."