Forget how many angels can dance on the head of a pin.

How many views on gender, sexuality, and church authority can fit under one church steeple?

Should gay clergy be ordained? Are same-sex unions blessed before God the same as the marriage of a man and woman? May a woman lead a church?

American Protestantism can be a free-for-all when supposedly like-minded believers get together. And this summer, as Presbyterians, Lutherans, American Baptists and others meet to choose leaders and set policy, these touchy topics may dominate--or derail--their agendas.

''There are no higher stakes. This is about salvation,'' says the Rev. Eileen Lindner of the National Council of Churches. She dubs this time of year ''the annual summer bloodletting.''

Most groups will commit souls and dollars to campaigns for evangelism, peace, and social justice. Some may tussle over theology, even argue about the meaning of Christ. The two largest Lutheran denominations each will elect a new presiding bishop.

Yet the spotlight is on a three-letter word--and it's not G-O-D.

''Sexuality is so incredibly important, so central to the human experience. Intimacy and transcendence are precisely what is at issue,'' Lindner says. ''No one is ambivalent. If there is middle ground, it hasn't been surveyed yet.''

For committed believers, the one in three Americans who attend church each week, these issues can be critical. Currently, a mere handful of the nation's 375,000 religious congregations call themselves ''welcoming and affirming'' or ''reconciling.'' Such phrases signify that gay, lesbian, bisexual and transgendered people are accepted in the church with the same rights, responsibilities and opportunities as heterosexuals.

Many more churches are equally open to sexual minorities and every variation of humanity, but don't list categories on their front door.

Yet American Baptist Church minister William Nicoson says most churches are like his: ''We're welcoming, but we're not affirming.''

His denomination calls homosexuality ''incompatible with Christian teachings.'' Nicoson, a leader in American Baptist Evangelicals, says, ''We believe homosexuality is one of the many sins of humankind. We are all broken by sin.''

But, he says, American Baptist Church congregations can't worship, evangelize and serve the community with churches that approve ''a lifestyle contrary to God's word.''

Last year, four churches were expelled (''disfellowshipped'') by their regional American Baptist Church associations for welcoming gay clergy and same-sex unions. They were allowed to stay under the national denominational roof only if they could find another association to offer them a philosophical home.

Thus, First Baptist Church of Berkeley, Calif., led by the Rev. Esther Hargis, a lesbian who welcomes all kinds of families, is now associated with the American Baptist Church in Wisconsin.

''We're Baptists,'' says Hargis, ''and this means each church has the right to call its own pastor. People can scream and threaten. They can push the church to the edge of involvement. But they can't really tell them no.''

Chris Glaser, editor of Open Hands , the welcoming Web site for seven U.S. and Canadian denominations, says many gay Christians long to return to their Christian roots, ''but they've been forced to make a false choice between their sexuality and their spirituality. We want to say, 'Please come back into the church.' ''

The battle is ''profoundly theological. Underneath, it's all about the authority of Scripture and how we proclaim Jesus Christ in an increasingly diverse world,'' says Jerry Van Marter of the news service for Presbyterian Church USA.

In 1998, the Presbyterians called for a three-year moratorium in their annual heated debate over standards of ordination requiring ''fidelity in marriage and chastity in singleness.'' The topic returns to the agenda this month, but it appears both sides used the cease-fire to re-arm.

''We were supposed to dialogue on unity in the midst of diversity, but everyone refused the olive branch,'' says the Rev. Joe Rightmyer of Louisville, of the conservative Presbyterians for Renewal.

A conservative group is calling for the national leadership to set a standard that Jesus Christ alone is the way to salvation; the Bible is the ''only infallible rule of faith and life; and the marriage between a man and a woman is ''the only relationship within which sexual activity is appropriate.''

Critics say such planks are anti-ecumenical and devalue believers' personal spiritual experience of God and the Scriptures.

But Parker Williamson, editor of The Layman and a leading voice for conservative Presbyterians, says, ''A church should have one message for the world on how it lives out its beliefs.''

His belief: We are all sinners. Pick your sin. The church has never said only the perfect are welcome. But in leadership we expect a certain standard of behavior. That behavior is defined by Scripture, and it rules out all forms of sex outside the covenant of marriage between a man and a woman.''