Most popes have served until their deaths. Benedict is the first in 600 years to resign.
He cited his health and age in announcing his retirement Monday. There have been no attempts to disguise his advancing age. It's known he has arthritis, and he occasionally uses a cane. A moving platform takes him down the aisle in St. Peter's Basilica.
Father Michael McCarthy at Santa Clara University's Ignatian Center for Jesuit Education thinks Pope Benedict's decision to retire was motivated by his predecessor.
"He had served under a pope, John Paul II, who was incapacitated for the last several years of his pontificate, and I think he probably saw as an insider that this has significant liabilities for the church," McCarthy said.
Still, parishioners in San Jose wonder if they're getting the whole explanation. "There's probably another reason, not just an illness or something," Ana Avalos said.
As one door closes, another opens as an increasingly diverse college of cardinals will vote for the new pope. The greatest growth in members for the Catholic Church has been in Latin America.
"I think it would be very interesting to have a pope from Africa or a pope from Asia or a pope from Latin America, and my guess is that that's probably -- I have no insider knowledge -- but my guess is that that is on peoples' minds," McCarthy said.
George Wesolek, a spokesman for the Archdiocese of San Francisco, praised Pope Benedict for making a difficult decision. "This is really an act of boldness on the part of this pope and also an act of great humility," he said.
However, some parishioners criticized the Pope for not articulating support for immigration reform. He hasn't really talked about immigration reform, said Avalos. "He should be talking about it because there are students who graduate but they don't have the opportunity to work," she said.
