SALT LAKE CITY - The president of the Mormon church announced Saturday that its worldwide membership has hit 15 million - a three-fold increase over the last three decades - as the Utah-based faith "spreads across the earth" on the strength of the largest missionary force in history.

The Church of Jesus Christ of Latter-day Saints president Thomas S. Monson made the announcement Saturday morning during a two-day church conference in Salt Lake City.

"The church continues to grow steadily and to change the lives of more and more people every year," Monson told about 20,000 members seated in a three-story auditorium in Salt Lake City. "It is spreading across the Earth as our missionary force seeks out those who are searching for the truth."

Monson said the church was founded with 30 members in 1830, and that it took more than a century to hit 1 million. Church membership has tripled since 1982 when there were 5 million members, said Matt Martinich, a member of the LDS church who analyzes membership numbers with the nonprofit Cumorah Foundation.

More than half of all Latter-day Saints live outside of the U.S., church figures show.

Mormons are still vastly outnumbered by other religious denominations such as Catholics, 1.2 billion worldwide, and Jews, 13.8 million, according to data from the Pew Research Center. But the Mormon faith is also much younger than those churches, having been founded in 1830, and is among the fastest-growing churches in the world.

Monson, considered the prophet of the church, said Saturday that there are now 80,000 missionaries around the world - up from 58,500 a year ago. The historic growth was triggered by the church's decision to lower the minimum age for missionaries, which Monson announced during this same conference a year ago.

By allowing men to go at 18, instead of 19, and women at 19, instead of 21, a wave of new, younger missionaries have joined older ones that were already planning to go.

The reaction from young Mormon women has been especially enthusiastic. The number of female missionaries has more than doubled in the last year to 19,000 currently, church figures show.

The biannual general conference brings members together to hear inspirational words from church leaders and to hear church announcements. In addition to the people in Salt Lake City, the conference is also watched by millions more around the world on TV, radio and the Internet. The conference is widely followed and analyzed on social media, with many using the Twitter hash tag, "#LDSconf."

Many of the speeches come from the church's Quorum of the Twelve Apostles, which is the second-highest governing body of the church. Modeled after Jesus Christ's apostles, the twelve men serve under the church president and his two counselors.

The ongoing debate about the limited role of women within the Mormon faith came to the forefront Saturday afternoon during a speech from D. Todd Christofferson, a member of Quorum of the Twelve. He said having women at home remains an essential part of society, saying that the "moral force" of women that kept societies on the righteous track for generations.

He criticized feminist thinkers who view "homemaking with outright contempt," and he cautioned against blurring feminine and masculine differences.

"In blurring feminine and masculine differences, we lose the distinct, complementary gifts of men and women that together produce a greater whole," Christofferson said.

He later implored women to dress modestly, and be good and virtuous. "We have enough women of fame and fortune; we need more women of faith," he said repeating what a former high-ranking woman in the church said.

Earlier in the day, Carole M. Stephens, first counselor in the General Relief Society presidency, said both men and women are given "priesthood power" when they go to Mormon temples, but that the two genders have different gifts and strengths. Citing a bible verse, Stephens said the Lord's plan emphasizes that men and women fulfill their responsibilities so that all may benefit.

Later Saturday afternoon, a feminist Mormon women's group called Ordain Women plans to ask to be let in an all-male priesthood meeting to highlight what they perceive as gender inequality. Though it's being broadcast live to all for the first time, the group still plans to wait in line to shine light on what they perceive as gender inequality in the faith.

Women can hold many leadership positions in The Church of Jesus Christ of Latter-day Saints, but they can't be bishops of congregations or presidents of stakes, which include a dozen congregations.

Other speakers during a pair of two-hour sessions offered instructions on how to be devout, contributing members of the church.

Robert D. Hales, a member of the Quorum of the Twelve Apostles, told church members Saturday that the "world is moving away from the Lord faster than ever" and instructed members to take the words of church leaders to heart.

Another member of the quorum, David A. Bednar, implored Mormons who don't tithe 10 percent of their income to the church to seek forgiveness. "Please do not procrastinate the day of your repentance," he said.

During the final speech of the morning session, Dieter F. Uchtdorf, one of Monson's two counselors, told the congregation that wrestling with doubt and serious or sensitive questions about the faith is normal. But he said, "please first doubt your doubts, before you doubt your faith."