The Roman Catholic Church has been the most successful iteration of Christianity to date. As of 2013, there were an estimated 1.2 billion Catholics in the world. Professional clergy and lay ministries work together to fulfill the ministry and mission of the Catholic Church. Ministries operated by laity are known as "apostolates," and they fulfill specific functions in the church and the world.

Local Apostolates

Catholic apostolates can take many forms. They may consist of local small associations of Catholics, such as a youth group associated with a specific parish or several parishes. The ministry that parents have with their children by teaching them in the faith is also considered an apostolate. Laity who participate in local Catholic education, whether in academic education via Catholic schools or in religious education via the church's various teaching ministries are involved in the work of an apostolate.

Apostolates and Social Issues

There are a number of apostolates dedicated to addressing Catholic social issues. In particular, there are a many pro-life apostolates that seek to promote the Catholic understanding of birth control, abortion, the death penalty and related issues. The Jesuits have organized several apostolates centered around social justice, both in the United States and abroad. Other apostolates promote the Catholic teachings on marriage, the family, family life and family structure.

Professional Apostolates

Some apostolates utilize Catholics in professional fields to do work that helps promote the mission and ministry of the church. For example, the Center for Applied Research in the Apostolate (CARA) at Georgetown University collects statistical data regarding Catholic ministry and makes that data available for parishes and other Catholics to use. Catholic Answers is an apostolate that publishes information about Catholic beliefs, the church itself and related issues online in an effort to promote the faith.

The Vatican's View

The leadership of the Catholic Church recognizes the need for laypersons to be involved in the work of the church. As such, the Vatican encourages the development of apostolates. Pope Paul VI, for example, encouraged parish priests to support these lay ministries and to help nurture and grow them. The Vatican is clear that while apostolates may perform similar duties and support the work of the clergy, apostolates are still subject to the church hierarchy.