The church, with its more than 14.1 million members, has 139 operating temples worldwide and has another 29 planned or under construction.
At a later news conference, Jeffrey R. Holland, of the Quorum of the Twelve Apostles, said church leaders were unsure how many more missionaries would serve due to the lowered age requirements but they expect a boost.
He also said leaders considered extending the length of missions for women to two years, but decided to see how the lower age goes first before possibly taking that step, The Salt Lake Tribune reported.
Tens of thousands of Mormon faithful were gathering in Salt Lake City through Sunday for the general conference.
1) Enter His Email Address 2) See Hidden Pics & Social Profiles Now!