He's not talking gay marriage, even though Frum will not change the shift. We can't push marriage, if marriage has been defined as sometime else.
But we're stuck with a problem like Leah. Public opinion moved in favor of gay marriage and young adults do not see the secular public policy concerns that have grown over the decades. A real problem which we must address.
As candidate Barack Obama told a Chicago church in 2008:
"(C)hildren who grow up without a father are five times more likely to live in poverty and commit crime, nine times more likely to drop out of schools, and 20 times more likely to end up in prison. They are more likely to have behavioral problems, or run away from home or become teenage parents themselves. And the foundations of our community are weaker because of it"
But the President's opinion has evolved, and what he said five years ago doesn't matter.