Katie Couric of Yahoo Global News sat down with Lyndon B. Johnson's daughters Tuesday to discuss civil rights at their father's presidential library, which is hosting this week's Civil Rights Summit. The event has attracted four presidents and countless civil rights leaders to celebrate the 50th anniversary of the Civil Rights Act of 1964, and to discuss the current battles over civil rights.

Luci Baines Johnson and Lynda Bird Johnson Robb both said they supported same-sex marriage, one of the civil rights issues that has already been discussed at length at the conference. “It’s a great civil rights concern of our day,” Johnson said.

Robb added, "We all have friends who are gay ... I certainly think that, if God made you a homosexual, that you should have love and affection with somebody. And I would not want to deny anybody that opportunity to be happy.”

They wouldn't venture to say whether their father would have also supported the issue. “It's hard to project what Daddy would have thought about that," Robb told Couric, "because that wasn't an issue that had come upon the stage at that time. But I know he really wanted everybody to be able to live up to the best that God gave them.”

In this July 2, 1964 file photo, President Lyndon Johnson signs the Civil Rights Act in the East Room of the White House in Washington. Standing from left, are Sen. Everett Dirksen, R-Ill.; Rep. Clarence Brown, R-Ohio; Sen. Hubert Humphrey, D-Minn.; Rep. Charles Halleck, R-Ind.; Rep. William McCullough, R-Ohio; and Rep. Emanuel Celler, D-N.Y. The Lyndon Baines Johnson Presidential Library in Austin is hosting a civil rights summit this week, highlighted by a keynote address by President Obama. (AP Photo, File)

Johnson agreed that the lens through which her father viewed civil rights was consistent with the spirit of the same-sex marriage movement. “I think my father felt very strongly that when there was bigotry anywhere, prejudice anywhere, all of us lose out. Because it's just one more expression of hate.”

Looking at how civil rights for blacks have changed since 1964, they admitted there was no doubt work remained. “I don't know how we could have expected to have enslaved a people for 100 years and then pass a law and think instantly everything was going to be made better,” Johnson said. “It takes time.”

The sisters also spoke about other areas of their father's legacy, and what it was like to live in the White House. Johnson said about the Vietnam War, “There's no doubt it was the agony of his life.” They also said LBJ would have been "proud" to see President Obama elected president.

As for living with the Secret Service, it could definitely be "awkward," they said. Robb had to go on her honeymoon with a Secret Service detail in tow, and Johnson was over 30 and divorced before she ever got to go on a date alone.

The LBJ Presidential Museum has a new exhibit on the "cornerstones of civil rights" that coincides with the Civil Rights Summit and is open all month.