Pope Benedict says goodbye to Vatican: Does the future of the church depend on celibacy?

Pope Benedict XVI addressed the crowds in St. Peter's Square Thursday one last time as the leader of the Roman Catholic Church.

About 150,000 people were cheering, with signs saying thank you to the pope. The pope met with the more than 100 cardinals who will choose his successor.

One by one, each clasped his hand and kissed his ring in a sign of reverence.

'I'm just a pilgrim,' Benedict XVI says in public farewell

As the pope steps down and joins his flock as another 'pilgrim,' can the church, which counts 1.2 billion people in its membership keep growing and remain relevant?

In the United States, since 1965, the number of priests has dropped nearly 35% percent, and the number of nuns plunged 70 percent.

Is celibacy the reason?

Is celibacy hurting the Catholic church?

OutFront tonight: Father Albert Cutie left the church after his relationship with a woman became public and Mary Johnson left the sisterhood because of the celibacy vow. She's also the author of a new book called "An unquenchable thirst." And Father Edward Beck is a celibate priest and host of "The Sunday Mass."