SALT LAKE CITY -- The Presbyterian Church (U.S.A.) appears ready to turn the corner on one of the largest membership losses in the history of Christianity, according to a new three-year study of the church.

The Presbyterian Church, which reached a high of about 4.4 million members in the mid-'60s, lost more than 43,000 last year, leaving membership of less than 2.9 million.

The study entitled "Presbyterians in the 20th Century: A Case Study of American Protestantism," involved 55 projects done by 65 researchers, said the Rev. John Mulder, president of the Louisville Presbyterian Seminary. The first volume of a projected seven-volume series on the study was released last month.

In an interview at the General Assembly meeting, Mulder said demographics played a large role in the denomination's decline. The postwar baby boomers have delayed marriage and having children, and are having fewer children overall.

But that doesn't fully explain the disproportionate losses endured by principal churches, said Mulder, who is also one of the directors of the study.

He said the research, funded by the Lilly Endowment, showed thatmany young people who grew up in mainline churches are not leaving for other churches, but are giving up on organized religion. Mulder said the "porous" kinds of religious traditions in the churches makes it "easy to join, but it's also easy to leave."

The study found an increasing pluralism in beliefs and moral behavior that puts the church at "risk of losing a clear and well-defined identity," Mulder said.

He also said the church suffered some "self-inflicted blows" by reducing its support for new church development and campus ministry.

Mulder said a group of people in the church are finding a middle ground between the liberals and conservatives.

"What we're seeing in the '90s is this mobilization of the moderate middle," Mulder said. "I would look toward the middle or the late '90s as the point the Presbyterian Church would begin to reverse some of the losses, or at least stabilize."

The church adopted evangelism and church development as its two priority goals at its General Assembly last year.

At the recent General Assembly meeting here, Stated Clerk James E. Andrews, the denomination's chief executive, said the effort is starting to pay off.

Adult and infant baptisms have increased, he said, as have professions of faith.