Steve and Marianna Richardson are parents 12 times over.

They’re about to increase that number to 200.

The Redmond couple is packing up their life and four of their children, and moving to Brazil to lead a mission of 200 young men and women.

This month, they’ll leave behind eight children, eight grandchildren and the Sammamish and Redmond communities that they have grown to love over the past 17 years. Steve has been the president of the Redmond stake of the Church of Jesus Christ of Latter Day Saints for nine years. In the Mormon Church, each stake is made up of geographical wards. The Redmond stake has nine wards and about 3,300 to 3,400 members, and the Seattle area has about 20 stakes.

“The thing I will always remember the Richardsons most for is their ability to help lift people up,” said Lee Hilton, who worked with the couple through the church. “Steve has been an especially wonderful champion of young people. He is savvy about the difficult challenges that face teenagers today, and has had a significant impact, both as a church leader generally, and working one-on-one with teens, to help them recognize their own strengths and assist them in realizing their dreams.”

Now, church leaders have asked the Richardsons to head up one of several missions in San Paulo, Brazil — a metropolis larger than New York City.

“They say that of all the things people do in the church, this is the most rewarding and the most challenging,” Steve said.

Steve was a missionary in Brazil 35 years ago, when there were perhaps 45,000 members of the Mormon church in the country. That figure has swelled to more than 1 million — in fact, about 65 percent of the young missionaries that the Richardsons will oversee are Brazilians. Brazil is the fifth-largest country in the world, with a population of more than 184 million.

“We’re excited. It’s going to be fun,” Marianna said.

Steve and Marianna’s new titles will be mission president and companion. But really, they’ll be parents and teachers to the young Mormons, most of whom will be serving away from home for the first time.

Most of the young missionaries volunteer for 18 to 24 months, and they give up not only their time but also earn the money ahead of time to pay for their stay while they serve. A typical missionary trip costs $11,000 to $12,000.

“It’s a total sacrifice. The benefits are amazing not only for the people they’re serving, but for themselves,” Steve said. “They come back — of course they have matured spiritually — but they come back learning how to love people and how to sacrifice for others.”

Marianna agreed, and added that missionaries come back better organized and able to set off in their own lives.

“They’ve learned another culture. They’ve learned another language. They’ve worked with people rich to poor,” she said. “They’ve seen people’s lives change. They’ve had doors slammed in their faces.”

In addition to leaving behind loved ones, friends and the large home they built for their expanding family nine years ago, Steve is also retiring from his position as principal researcher and manager of the Machine Translation group at Microsoft. He and three others started Microsoft’s research division 17 years ago after he left IBM in Maryland, where he had worked in research for 11 years.

The couple had eight children when they moved to the area. Now, their 12 kids span a range of ages from 8 to 30.

“It doesn’t matter how many you have. It’s always overwhelming,” Steve half-joked.

The youngest four are headed to Brazil with their parents. That group includes William, 16, Adam, 12, Clara, 10 and Deborah, 8. The older members of the Richardson family include Julia, 18, David, 20, Amy, 20, Sarah, 22, John, 24, Hannah, 25, Eric, 27, and Christina, 30.

When they had 10 children — perfectly balanced at five girls and five boys — they nearly stopped.

“Then we had Clara, No. 11, and Marianna said, ‘We can’t stop now. We’ve gotta have another one,’” Steve said.

As with parenting, teaching is also old hat for this pair.

Marianna has been involved in PTA for many years, the last four at Eastlake High School and the past two as co-president of the PTA.

“There just isn’t another person who has the heart of each and every student in her heart for all she does,” Eastlake Principal Rondel Hardie said. “That’s a true PTA leader who is there for all kids. She is just so much larger than herself, and is always giving of their time and energy to make our community all it can be for students.”

Before volunteering at Eastlake, Marianna also taught art at Emily Dickinson Elementary School and earned a doctorate in education from Seattle Pacific University.

Through their children, they’ve gotten to know teachers and educators over two decades at numerous schools. There have been football, soccer and other sports games too numerous to think of counting. In recent years, some of the children have gotten into the drama scene.

And, all of the children have been involved in helping community members through food drives, Scouting and youth group work.

“We feel strongly about the importance of supporting the community,” Marianna said. “We’ve really loved the community here.”