The Catholic Church has its share of critics, but few are as vocal as a group who labels its members part of the Catholic flock.

From contraception to gay rights to the death penalty, Catholics for Free Choice takes a position contrary to the church. The organization denounces the moral teachings of the church, condemns the Vatican and ridicules church leaders on a regular basis.

"Catholic bishops maintain the position condoms can't be used to prevent the spread of AIDS," Catholics for Free Choice President Frances Kissling said to demonstrate another area of divergence.

Progressive Catholics is the label used by the group, based in Washington, D.C., to portray itself. But critics call it nothing more than a handful of abortion activists masquerading as Catholics to use that credibility to win publicity and undermine the church.

Opponents point to CFFC's campaign to revoke the Vatican's seat at the United Nations as an example of its hostile view of the church.

"I think she is really guilty of false advertising. [Kissling] does not represent Catholics," Father Thomas Rausch of Loyola Marymount University said. "It seems to me that the label is more political. I have never seen any indication at all that she is a member of the Catholic community of faith."

In fact, Kissling spent six months as a nun in the 1960s. Now, she reportedly doesn't attend mass or pray.

"I spent 20 years looking for a government to overthrow without being thrown in jail, " she said. "I finally found one in the Catholic Church."

Unlike grassroots groups, funded by thousands of membership dues, records show the organization receives most of its money from liberal foundations. Its big-money donations include $375,000 from billionaire Warren Buffett; $600,000 from the Hewlett Foundation; $1.6 million from the MacArthur Foundation; $3.8 million from the Packard Foundation; and $4.4 million from the Ford Foundation.

Other notables include Ted Turner, who is known for mocking Catholics as "Jesus freaks" for marking Ash Wednesday. The Playboy Foundation and the Sunnen Foundation, a manufacturer of contraceptive foam, are also notable contributors.

Recently Kissling launched a worldwide billboard campaign blaming the church for Africa's AIDS epidemic because it opposes contraception.

While the group talks easily about the church, Catholics for Free Choice refused to talk about itself, telling Fox News they would only be interviewed if they were portrayed in a "positive" light. The demand was rejected.

Fox News' William LaJeunesse contributed to this report.