Republican Sen. Rob Portman recently announced a change of heart about gay marriage, saying that it should be allowed. Other Republicans responded after his announcement.

Hours after Republican Portman announced he had reversed his position on same-sex marriage, former House Speaker Newt Gingrich said he won't second-guess Portman, but he's not entirely embracing the Ohio senator's change of heart, either.

Portman told CNN's Dana Bash that after his 21-year-old son came out two years ago, he came to the conclusion that same-sex marriage "is something that we should allow people to do."

"To get married, and to have the joy and stability of marriage that I've had for over 26 years," Portman said. "That I want all of my children to have, including our son, who is gay."

Their son, Will, tweeted Friday morning, saying he is "especially proud of my dad today."

Gingrich acknowledged on CNN's "Starting Point" that when an immediate family member reveals that he or she is gay, there are typically three responses.

"You can say, 'I believe my principles so much, I'm kicking you out.' You can say, 'I still believe in my principles, but I love you.' Or you can say, 'Gee, I love you so much I am changing my principles,'" Gingrich said. "Rob picked the third path. That's his prerogative."

The former presidential candidate stands by his own belief that a marriage is between a man and a woman, and argued the traditional definition will stay in place "no matter what politicians decide."