Aug. 3, 2012 — -- Last summer, Laura, a young woman originally from the suburbs of Salt Lake City, became the first among her siblings to get married. This summer, she became a mother.
Getting married and having a child can be a heady time for anyone, but unlike most young married mothers, Laura, 19, knows that someday soon she could be in for yet another major life change: her husband could marry another wife.
"It's really hard when you actually fall in love and you love somebody so much to think of sharing them with somebody else," Laura told "20/20" last year. But, she added, "God changes people's hearts. You know sometimes there are things you don't think you can do but when God asks you, you do it."
Laura belongs to a community of independent Fundamentalist Mormons that includes her own parents -- her father, Joe Darger, her biological mother, Alina Darger, and Joe Darger's two sister wives, Vicki and Val Darger. They adhere to the tenet of plural marriage put forth by church founder Joseph Smith in the 19th century.
Last year, the Darger family -- which includes a total of 24 children -- took their polygamist lifestyle public. The Darger parents penned the book "Love Times Three," about their unconventional family, seeking to fight the negative stereotypes of polygamous families and hoping that someday, laws could be changed that would allow families like theirs to live without fear of prosecution. In Utah, where the Dargers live, polygamy is a felony punishable by as much as five years in prison.
"In the end it's not about the bedroom, it's not about all these outward things people are curious about. It's just about a family trying to raise responsible children," Val Darger said.
The Darger children, meanwhile, insist that they're normal kids and have spoken out in support of their parents. (Watch more from the Darger children here.)
But not all of the children have embraced polygamy. Caleb, 21, Vicki Darger's biological son, earlier this year joined the mainstream Mormon Church, the Church of Latter Day Saints, which disavowed polygamy more than a century ago.
In a blog post, Joe Darger wrote about the difficulty of having a son who had chosen to pursue a separate faith.
"It saddened my heart to think one of the most sacred and important parts of my lives was not fully connected with my son. Such is the consequence of choice," Joe Darger wrote. "I was both happy for him and sad for me. Choice by its nature means our children will not choose right all the time, or certainly will not choose what I think is right. Yet I believe that is God's plan as well. None of us do choose the way we should all the time. That is the reason for His grace."
Meanwhile, Caleb Darger's sister, Amanda -- Val's biological daughter -- has chosen a starkly different path. The 20-year-old has joined her fiance in a more traditional fundamentalist Mormon group in Arizona and has recently begun wearing more conservative, longer dresses and a bundled hairstyle.
Most of the Dargers, however, don't stand out from the crowd. They wear contemporary style clothing, play sports, attend school and college, and engage in hobbies like mountain climbing, baking and playing guitar.
The size of the family means that strict organization is a must: While Joe is the main breadwinner, the wives split up cooking dinner and other chores.
"It takes a lot of coordination and communication. Contrary to what many people think we get jealous about, it is this coordination and sharing that is often the most difficult," the Dargers say on their website.
The Dargers do admit they face challenges of jealousy and hurt feelings when it comes to romance.One of the rules that the Dargers live by to minimize these difficult moments is keeping the intimate details of each of their relationships with Joe private. (Watch what two sister wives do while the third is out on a date with Joe here.)
"We're very traditional in our marriage in the fact that we have three separate marriages and it's just a boundary of respect," Joe Darger said.
"Love Times Three" will be published in paperback Aug. 28.