rather than leaving to form new, break-away groups. Breakaway Presbyterian denominations Several Presbyterian denominations have split from PC(USA) or its predecessors over the years. For example, the Orthodox Presbyterian Church broke away from the Presbyterian Church in the USA (PC-USA) in 1936. More recently formed Presbyterian denominations have attracted PC(USA) congregations disenchanted with the direction of the denomination, but wishing to continue in a Reformed, Presbyterian denomination. The Presbyterian Church in America (PCA), which does not allow ordained female clergy, separated from Presbyterian Church in the United States in 1973 and has subsequently become the second largest Presbyterian denomination in the United States. The Evangelical Presbyterian Church (EPC), which gives local presbyteries the option of allowing ordained female pastors, broke away from the United Presbyterian Church and incorporated in 1981. A PC(USA) renewal movement, Fellowship of Presbyterians (FOP) (now The Fellowship Community), held several national conferences serving disaffecting Presbyterians. FOP's organizing efforts culminated with the founding of ECO: A Covenant Order of Evangelical Presbyterians (ECO), a new Presbyterian denomination that allows ordination of women but is more conservative theologically than PC(USA). In 2013 the presbyteries ratified the General Assembly's 2012 vote to allow the ordination of openly gay persons to the ministry and in 2014 the General Assembly voted to amend the church's constitution to define marriage as the union of two persons instead of the union of a man and woman, which was ratified (by the presbyteries) in 2015. This has led to the departure of several hundred congregations. The majority of churches leaving the Presbyterian Church (USA) have chosen to join the Evangelical Presbyterian Church or ECO. Few have chosen to join the larger more conservative Presbyterian Church in America, which does not permit female clergy. Youth Since 1983 the Presbyterian Youth Triennium has been held every three years at Purdue University in West Lafayette, Indiana, US, and is open to Presbyterian high school students throughout the world. The very first Youth Triennium was held in 1980 at Indiana University and the conference for teens is an effort of the Presbyterian Church (USA), the largest Presbyterian denomination in the nation; Cumberland Presbyterian Church; and Cumberland Presbyterian Church in America, the first African-American denomination to embrace Presbyterianism in the reformed tradition. Since 1907, Montreat, North Carolina has hosted a youth conference every year. In 1983, Montreat Conference Center became a National Conference Center of the PC(USA) when the northern