A US evangelical church faces being kicked out of its Baptist convention next month if it fails to reverse its decision to admit gays to all aspects of church life including marriage and ordination.

The First Baptist Church of Greenville in South Carolina voted in May not to discriminate against the right of gay, lesbian, bisexual and transgendered people either to belong to the church, to be married or to be ordained.

The church stated: "In all facets of the life and ministry of our church, including but not limited to membership, baptism, ordination, marriage, teaching and committee and organisational leadership, First Baptist Greenville will not discriminate based on sexual orientation or gender identity."

Greenville First Baptist left the Southern Baptist Convention in the 1999 but is listed by the South Carolina Baptist Convention as one of its churches.

First Baptist is also affiliated with the Cooperative Baptist Fellowship, regarded as on the more liberal wing of Baptist organisations. The fellowship stated: "The foundation of a Christian sexual ethic is faithfulness in marriage between a man and a woman and celibacy in singleness."

Southern Baptist Convention president Ronnie Floyd told South Carolina's Baptist Courier: "My heart was grieved when I heard of the decision made by the First Baptist Church of Greenville."

South Carolina Baptist Convention president Tommy Kelly said: "While Southern Baptists embrace such principles as local church autonomy and the priesthood of individual believers, these principles should never trump biblical authority."

According to Matthew 19:4-5, marriage is between one man and one woman within a covenant relationship.

Kelly said the decision to allow gay people to be ordained was "in direct opposition to biblical precedent and standard."

First Baptists senior pastor Jim Dant defended the move. He said: "There's no family value system in the Bible that we would lay into the 21st century. We don't have two wives and sleep with our maids and have a bunch of children and that be fine. What we believe about marriage and family is culturally driven, not biblically driven."

Dwight Easler, chairman of the South Carolina Baptist Convention, has demanded that Greenville First Baptists either recant or withdraw from the convention by 10 September. If they do neither, they are expected to be voted out by the convention.

The influential conservative blogger Albert Mohler, president of Southern Baptist Theological Seminary, wrote this week that the move by the Greenville First Baptists came after the church had undergone a "discernment" process under the leadership of a "LGBT Discernment Team".

He described how the congregation, now more than 180 years old, is one of the most historic churches in the South and was a founder member of the Southern Baptist Convention in 1845.

The church was largely responsible for the birth of Furman University and its old "church house" became the first home of The Southern Baptist Theological Seminary in 1859. "Few churches in the South can match its historical record," he added.

It became more liberal in the 20^th century as the Southern Baptist Convention became more confessional and affirmed the inerrancy of Scripture.

"Once a church or denomination is untethered from the inerrancy of the Bible, there is no brake on the relativising effects of cultural pressure," wrote Mohler. "There are big lessons here for every church, every denomination, and every Christian institution. Once biblical inerrancy is abandoned, there is no brake on theological and moral revisionism. The Bible's authority becomes relative, and there is no anchor to hold the church to the words of Scripture and 2000 years of Christian witness."