A posting by the Catholic News Service looks at that question — and finds some intriguing theories:

Statistics leave no doubt that the number of women religious has dropped sharply over the last 50 years, but there is an ongoing debate over the reasons for the decline.

The question surfaced recently when L’Osservatore Romano, the Vatican newspaper, asked one priest to review another priest’s book about the phenomenon.

Italian Claretian Father Angelo Pardilla, author of “Religious Yesterday, Today and Tomorrow,” said the principal cause for the decline was that many religious misunderstood the teaching of the Second Vatican Council and lost a sense of their identity.

He cited as proof the fact that the number of vowed religious — both men and women — has dropped sharply since Vatican II, except in the contemplative orders that still wear habits and live with a regimented community life.

But Father Giancarlo Rocca, a scholar of the history of religious orders, questioned Father Pardilla’s thesis in the review he wrote for the Vatican newspaper.

Father Rocca agreed with Father Pardilla that factors contributing to the decline include materialism, secularism, the anti-authority movement of the late 1960s and declining family size.

But he said a misreading of the Second Vatican Council could not be the prime culprit, because in many places the numbers began to drop in the 1930s, long before the council opened in 1962.

For Father Rocca, the key is the emancipation of women.

Continue for the rest and see what you think.