FRESNO, Calif. — Reiko Elledge of Clovis, Calif., doesn't want to be disturbed from 6:15 to 7 p.m. Mother's Day, tomorrow. It's reserved for a long-awaited phone call with son Christopher, a Mormon missionary currently in Belo Horizante, Brazil.

Mother's Day is one of just two days a year when Mormon missionaries are allowed 45-minute phone calls from home. The other is Christmas Day. Missionaries are allowed to call home for a brief chat of a couple minutes before those two days to set up a time and to give a phone number for the parent to call.

Several days ago, Elledge and her son made their arrangement. She says she'll use a speaker phone so six other family members can join in the call.

"We'll come out of church service, then call after Sunday dinner," says Elledge, an office worker in the graduate studies department at California State University-Fresno. "Everyone will be there."

More than 35,000 missionaries from the United States are currently serving overseas or in the United States and Canada.

The Church of Jesus Christ of Latter-day Saints has been sending out missionaries since the 1830s, soon after the church was founded. The early missionaries were mainly men with families. Now they are mainly young unmarried men. There also are young unmarried women missionaries.

The church requires men to become missionaries at age 19. It gives women the option to become missionaries at age 21. Missions range from 18 months to slightly more than two years.

Stake presidents oversee the missionaries — and encourage them to write weekly letters to family or e-mail them through public computers such as at Internet cafes.

However, stake presidents — a stake is a group of several Mormon congregations — place restrictions on the number of phone calls. Families are on their honor to adhere to that. The church wants missionaries to remain focused on the task at hand.

Typically, missionaries visit other people's homes to share their faith, and work with local churches in helping others.

Mother's Day and Christmas Day are the phone-call days because they are holidays that are important to the Church of Jesus Christ of Latter-day Saints — and they are spaced at least five months apart.

Reiko Elledge's oldest son, Nathan, 23, was on a mission in Fukuoka, Japan, from June 2003 to August 2005. Christopher, 21, began his mission the month after his brother completed his.

Born and raised in Tokyo, Reiko Elledge was familiar with the area Nathan was serving in Fukuoka, which includes southern islands such as Okinawa and Ishigaki. Still, she worried.

"You're hoping people would treat them as they would want to be treated," she says.

Initially, she worried also for Christopher, after hearing that residents of Belo Horizante had thrown rocks at some Mormon missionaries.

"That is a sad thing," she says. "I was worried bad people would attack him."

Christopher Elledge has three months left and has served without incident.