Luci Baines Johnson and Lynda Bird Johnson Robb, daughters of former President Lyndon B. Johnson, have endorsed gay marriage.

Speaking with Katie Couric at their father's presidential library in Austin, Texas, Johnson called denying loving gay couples the right to marry a “tragedy.”

When asked whether their father – who pushed for passage of the landmark Civil Rights Act of 1964 – would have supported marriage equality, the women said social issues were important to him.

“It's hard to project what Daddy would have thought about that because that wasn't an issue that had come upon the stage at that time,” Robb said. “But I know he really wanted everybody to be able to live up to the best that God gave them.”

“I certainly think that, if God make you homosexual, that you should have love and affection with somebody. And I would not want to deny anybody that opportunity to be happy,” she said.

“I think my father felt very strongly that when there was bigotry anywhere, prejudice anywhere, all of us lose out,” Johnson said. “Because it's just one more expression of hate.”

“It's a great civil rights concern of our day,” Johnson added.

(Watch the full clip at Yahoo! News.)