WHEN CONSTRUCTION on the 200-foot tall Church of Jesus Christ of Latter-Day Saints (LDS) in San Diego, Calif., was completed in 1993, the public was invited. More than 720,000 of the curious, including members from an array of Catholic groups—from singles clubs to parish women's groups—got a glimpse inside the usually off-limits massive white structure.

After two months of tours, the temple was dedicated. Now access is reserved to LDS adherents with so-called temple “recommends” (that verify good standing in the faith). Still, though the temple doors closed some three years ago, interaction continues between Catholics and Latter-Day Saints, the name preferred by worshippers also known as Mormons.

Earlier this year, temple members brought valentines and centerpieces decorated with cookies to Brother Benno's Foundation, a San Diego County facility founded by a local Benedictine monk to help the working poor and homeless. “I think such [interfaith outreach] is great,” said Jim Kutler, who helps run the foundation. “The poor and other social causes are everybody's responsibility.”

Indeed, LDS members and Catholics are in accord on a number of social issues, according to representatives from both Churches. There are, however, significant theological differences.

The Catholic Church has no detailed position on Mormonism, except concerning the Mormon baptism, said Msgr. M. Francis Mannion, rector of the Cathedral of the Madeleine in Salt Lake City, Utah. Msgr. Mannion is theological advisor and ecumenical officer for the Diocese of Salt Lake City, the city that is also home to the headquarters for the Mormon Church. “Mormon converts to Catholicism are baptized conditionally, since there exists doubt about the validity of Mormon baptism. However, in certain cases, Mormons are treated as validly- baptized Christians. There is a certain ambiguity which has not yet been resolved,” he said.

The two Churches have had no formal contact at the national level, said Dr. John Borelli, director of the U.S. Catholic Conference's (USCC) Office of Ecumenical and Interreligious Affairs. However, he said the Catholic Church is “somewhat cautious” regarding the Mormon's strong missionary tradition.

The Mormon religion was founded in 1830 by Joseph Smith in Fayette, N.Y., three years after he claimed to have received golden tablets from an angel that contained the Book of the Prophet Mormon. Today there are some 10 million members world-wide. Of the 4.2 million in the United States, 1.5 million live in Salt Lake City and another 800,000 in California. The Church's growth in the last two decades has been most prominent in Latin America, Africa and the former Soviet Union, said Keith Atkinson, Southern California public affairs director for the LDS.

Atkinson attributes the growth to several factors. “There is the focus on moral values, family, education and the health code,” he said. “You help somebody stop smoking and drinking, that's part of our health tenet.” An LDS code known as the “Word of Wisdom” prohibits smoking and the consumption of alcohol and caffeinated coffee and tea.

The LDS's missionary orientation provides a challenge to Catholicism, especially in Latin America, said Father Gregory Coiro OFM, a spokesman for the Archdiocese of Los Angeles. “There's a shortage of priests and thousands in a parish,” he said. “The [Arch]diocese of Mexico City has 20 million Catholics. It's very hard to carry on the faith. [When] another faith offers a rosy vision, it's easy for people to make the switch.”

Father Coiro said that LDS can't be defined theologically as Christians because of certain beliefs, including polytheism, that run counter to Christianity. But he added that “the truth issues rarely come up” when Mormons evangelize. Mormons don't subscribe to the doctrine of the Trinity, though they recognize three separate divine beings. They hold that God had a wife and that believers become gods of their own planets after death.

“That is not to say they don't believe in Jesus,” said Father Coiro. “They have a highly ethical code, [and an] emphasis on family, but when it comes down to it, they are another religion, like Hinduism.”

Mormonism, Msgr. Mannion said, fits the definition of what the Catholic Church calls “a new religious movement.” However, LDS members believe they are Christians. Said Atkinson: “We believe the Book of Mormon is another testament of Jesus.”

Christians and Mormons are most similar in morality-related concerns, said Msgr. Mannion. That interpretation was echoed by Father Jordan Lenaghan OP, a chaplain at the University of Virginia in Charlottesville, who has studied Mormonism. “Socially, they are Christians. The religion has a focus on Christ, good works and the new Testament,” he said. Father Lenaghan said the two faiths also share ecclesiastical traits, a historical orientation and a hierarchical leadership.

The LDS Church has ordinances that are similar in some respects to Catholic sacraments. A father's blessing is an ordinance bestowed on a child shortly after birth. After a few weeks, the child is also blessed before the congregation and given a name. At age eight, he or she has the choice to be baptized, said Atkinson.

For Latter-Day Saints, bread and water symbolize Christ. The religion also “confirms” its members and allows a male lay “priesthood,” while women belong to the “Relief Society.” Furthermore, there is a form of reconciliation. Mormons evaluate their worthiness for the temple “recommend” that provides access to the worship site where the highest ordinances of faith are formed. Bishops, who are similar to Catholic pastors, conduct the evaluation at least once annually.

Despite theological differences, Catholics and Mormons interact on some social issues, and relations between the two religions are generally friendly. Los Angeles Cardinal Roger Mahony, for example, invited Mormons to a Celebration of Life observance earlier this year. Like Catholics, LDS members oppose pornography, same sex marriages and euthanasia. They believe abortion is acceptable in the case of rape, incest or when the child is not expected to live beyond birth. Atkinson said the decision to abort may be made after “serious prayerful consideration,” fasting and consultation with ecclesiastical officials and medical professionals.

Like Catholics, Mormons believe one important purpose of marriage is procreation. While mindful of their duty to multiply, Mormon couples can opt for contraception for health reasons. Ultimately, birth control is a matter between the married couple and God, said Atkinson.

The Mormon Church has worked with Catholic Relief Services (CRS) at the height of Ethiopian and Sudanese droughts in 1986. “CRS had an established field presence in Ethiopia, with access to Sudan,” said Atkinson. Mormons, who tithe, also conduct special collections such as one taken up for Ethiopia. Mormons fasted and donated what they would have spent for meals. The $1.9 million raised through the effort was donated to CRS.

When the Cathedral of the Madeleine in Salt Lake City was undergoing renovation, Mormons chipped in $500,000 toward the effort. Atkinson said donors were guided by the 11th Article of Faith: “We claim the privilege of worshipping almighty God according to the dictates of our own conscience and allow all men the same privilege, let them worship how, where or what they may.”

But their have been some wrinkles in relations between Catholics and Mormons. “[Through] the years, the relationship has been occasionally difficult, especially in the area of proselytism and perceived dominance of the culture,” Msgr. Mannion said. Tensions are especially pronounced, he added, “in the public school systems, especially in rural areas, where non-Mormon children can feel discrimination or at least some insensitivity.”

But since the early 1980s, he continued, there has been a conscious effort by Catholic and Mormon leaders “to cooperate where possible, to coexist respectfully, yet to do so without any illusions regarding the deep differences that exist between the two Churches.”

Liz Swain is based in San Diego,Calif.