Freddie Schineller is a hip-looking math professor with a salt-and-pepper goatee. His artist wife, Holly, has long blond hair and stays home to take care of their four kids ages 8-12.

The middle-class family lives in a modest Tempe home full of lots of love, noise and pets, including two dogs and a python named Monty.

Their bookshelves hold works by Plato, Leo Tolstoy and Franz Kafka, as well as the Book of Mormon and a Bible.

But Holly and Freddie don't believe in God. And, earlier this year, they decided it was time to "come out of the closet" in a big way about who they are.

After a family meeting, the Schinellers volunteered to appear on a Valley billboard for a campaign by the Freedom From Religion Foundation, a national group that aims to boost social acceptance of atheists and spotlight the growing numbers of non-religious Americans.

"I don't necessarily want to change minds. I just want to dispel some of the myths," Holly said about appearing on the billboard.

A portrait of the smiling Schineller family appears on a billboard in Mesa, one of nine featuring Phoenix-area residents or families who describe themselves as atheists, agnostics or freethinkers, posted throughout the Valley. There are two in Tucson.

Wisconsin-based Freedom From Religion Foundation and its Phoenix-area chapter plastered the faces over billboards last month as part of its "Out of the Closet" campaign. They are expected to come down next week.

The campaign, featuring atheists who live in the community where the billboards are posted, started a year ago in Wisconsin and has run in Columbus, Ohio; Tulsa, Okla.; and Raleigh, N.C.

The foundation's members say the billboard campaign is a high-profile way of reaching the growing number of Americans questioning religion.

From 1990 to 2008, the number of adults in the U.S. who identified as having no religion increased from 14 million to 34 million, according to the 2008 American Religious Identification Survey, which questioned about 54,000 adults in the continental U.S.

The national survey by researchers at Trinity College in Connecticut tracks adult Americans' identification with religion.

The Freedom From Religion Foundation claims to have more than 17,000 members, with more than 400 in Arizona, and is considered the nation's largest association of atheists or agnostics.

About 17 percent of adults in Arizona are nonreligious, according to the 2008 survey, which is higher than the national average of 15 percent.

Foundation members from Tempe, Phoenix, Tucson, Chandler, Scottsdale, Avondale and Sun City wrote their own testimonials about their beliefs that they wanted to share with their Valley neighbors. Their words are featured on cheery-colored billboards alongside their portraits.

The Schineller family's bright-yellow billboard with daisies is near Main Street and Dobson Road.

It says: "Love + critical thinking = open minds." And below that: "The Schineller Family, Tempe ... Freethinkers."

Although Holly and Freddie are atheists, they didn't want to label their children.

While Holly hopes her children will follow in her footsteps when it comes to religion, it's more important to her that they are given an upbringing that is open-minded so they can make an educated decision about religion.

Chandler resident James Woods, who is blind, describes himself as agnostic. His billboard says: "Faith without reason is true blindness."

Joe Hernandez of Phoenix calls himself a vegan, microbiologist and atheist. His billboard says: "Good for goodness sake -- no gods required."

Below each message is the address for Freedom From Religion's website, which explains the group's efforts to create an umbrella network for the growing number of Americans who don't believe in God and its legal battles to uphold the separation between church and state in the U.S.

The non-profit foundation was founded in 1978 by Anne Nicol Gaylor, 85, and her then-college-age daughter, Annie Laurie Gaylor, now 56, who remains co-president with her husband, Dan Barker, a former evangelical minister. The younger Gaylor said her mother formed the foundation in response to what she saw as a brewing "religious war on women's reproductive rights" in the 1970s.

That early advocacy, Gaylor said, "opened our eyes to a broad attempt to put religion into government."

"We wanted to remind the nation of our secular heritage," she said.

This year, the foundation sued Gov. Jan Brewer for issuing proclamations in support of an Arizona Day of Prayer. The lawsuit, filed in federal court, claims that in declaring a state day of prayer, Brewer violated the Establishment Clause of the First Amendment of the U.S. Constitution.

That clause prohibits the government from establishing an official religion, from unduly favoring one religion over another and from unduly preferring religion over non-religion, or non-religion over religion.

Brewer's attorneys have asked the federal District Court in Phoenix to dismiss the lawsuit. They maintain that the Arizona Day of Prayer is voluntary, with residents free to choose whether to mark the occasion.

Gaylor said members in the Phoenix area believe a government-sponsored day of prayer shows preference for religion over non-religion.

Battling state and federal agencies in high-profile lawsuits draws the ire of religious extremists, Gaylor said, and foundation members and lawyers often get death threats or threats of violence related to its state-church separation campaigns.

Gaylor blames anti-atheist prejudice for the threats and more common discrimination against atheists in the workplace or community.

A recent study by researchers at the University of British Columbia suggested that fear and prejudice against people who do not believe in God are seeded in distrust.

Researcher Will Gervais' surveys of 351 American adults and 417 UBC students suggested participants perceived atheists to be the least trustworthy and most likely to commit a crime when compared with Muslims, Jews or others who belong to a religious group, homosexuals or feminists.

The only group of people they distrusted as much as atheists was rapists, according to the study, published in the latest peer-reviewed Journal of Personality and Social Psychology.

"This is how bad the prejudice is? We're up there with criminals," said Gaylor, who describes herself as a third-generation freethinker.

Gaylor believes that fear has resulted in censorship of atheists' ideas and that advertising companies across the country have refused to run their ads. Agencies sometimes acknowledge they fear complaints from consumers who view the billboards as promoting atheism, she said.

Gaylor said CBS Outdoor refused to run their current billboard campaign in Phoenix. Although CBS Outdoor ran their 2008 campaign, which featured catchy slogans but no photos, Gaylor said she could not use billboards near schools. A similar policy often applies to ads promoting alcohol or tobacco.

CBS Outdoor, which runs the "I'm a Mormon" campaign, aimed at debunking misconceptions about the religion, on Phoenix billboards, declined to comment for this story.

"Atheists are still considered social pariahs," Gaylor said.

She said the foundation hopes the "Out of the Closet" campaign will make atheism more mainstream and help people understand that atheists are not bad people.

"We're saying, 'This is your friendly neighborhood atheist,'" she said. "It's harder for people to be hateful when they know you. Would you be hateful to the Schineller family, to their lovely children?"

Holly Schineller doesn't think a billboard will stop some people from hating her because she doesn't believe in God. She has accepted that the religious culture in America is so strong now that life for an atheist is "pretty polarizing."

But she said it will be a step in the right direction if the billboards just make the people who know her family, but didn't know she was an atheist, start to think differently about atheists as group.

"We are very much about personal responsibility," she said.