NEW YORK • One of the largest social service networks in the United States, working in areas ranging from adoption to disaster relief, faces a shake-up because of Lutheran divisions over the Bible and homosexuality.

The Lutheran Church-Missouri Synod, a theologically conservative denomination headquartered in Kirkwood, Mo., said Wednesday that direct work with its larger and more liberal counterpart, the Evangelical Lutheran Church in America, has become "difficult if not impossible," because of doctrinal conflicts, including the 2009 decision by liberal Lutherans to lift barriers for ordaining gays and lesbians.

Neither denomination would discuss the potential financial impact Wednesday. Many Lutheran-affiliated agencies receive substantial state and federal grants that would not be directly affected by any split. However, similar to Catholic Charities, Lutheran agencies are some of the biggest service providers in their communities.

"We recognize that this is a difficult issue. It's complicated," said the Rev. Herb Mueller, first vice president of the Lutheran Church-Missouri Synod. "We're trying to take a nuanced and caring approach to all of these situations that's also faithful to what the Bible teaches on these issues."

The Rev. Donald McCoid, an ecumenical officer for the Chicago-based Evangelical Lutheran Church in America, said: "We are deeply concerned about the ministries of care that may be challenged by the recent action of The Lutheran Church-Missouri Synod."

The 2.3 million-member Missouri Synod has been studying the issue for more than a year. This week, the panel issued a 15-page document of guidelines for churches, congregants and ministries deciding whether they should cut off any direct joint work with the Chicago-based Lutherans.

The only immediate announced break was for the Missouri Synod to stop its decades-old practice of training military chaplains with the Evangelical Lutheran Church in America. The president of the Missouri Synod, the Rev. Matthew Harrison, said in a statement that the decision, effective next year, was based on the ELCA decision on gay ordination, and on the military's plan to repeal the "don't ask, don't tell," policy. However, the guidelines for evaluating the joint relationships made it clear that cooperative work in many of the agencies is likely to end.