It was her first international AIDS conference, in 2004 in Thailand. Just two years earlier an article on how HIV was devastating African families led Kay Warren to take up the cause when very few conservative Christian leaders were doing so. She chronicles her journey into activism in her new book, Dangerous Surrender: What Happens When You Say Yes to God, which is a plea for fellow believers to join the fight.

'I think there are some people who won't get past the first few chapters. It's not a light read,' says Warren, whose husband wrote the multimillion-selling The Purpose Driven Life. 'For some people, it will come at the right time for them.'

It was only a few years ago that evangelicals began tentatively putting their energies into combating the infection. Many conservative Christians considered the illness a punishment from God--for same-gender sex, prostitution, and drug use. AIDS activism also inevitably meant working with gay leaders, whom evangelicals had been battling over same-sex marriage.

As recently as 2006 the Barna Group, which specializes in researching the views of conservative Christians, conducted a survey in which two out of five born-again Christians said they had more sympathy for people with cancer than for those living with HIV. That attitude has been changing. International Christian relief groups such as World Vision have been taking U.S. pastors to visit AIDS-ravaged communities in Africa. U2 front man Bono, citing his own faith, barnstormed the United States, pressing President Bush and other U.S. leaders to do more to stop the pandemic.

Three years ago the Warrens began organizing the annual Global Summit on AIDS and the Church, held at Saddleback Church, the megacongregation they started in Lake Forest, Calif. Bill and Lynne Hybels of the Willow Creek Association of megachurches offer an annual Courageous Leadership Award to churches with the best programs to combat the disease.

'I think there has been a sea change,' says Steve Haas, vice president for church relations at World Vision. 'James 1:27 states that pure and unadulterated religion is that you take care of the orphans and widows in their distress. The greatest orphan and widow creator of all time is upon us. It's called AIDS.'

Yet Haas and Kay Warren say everyday evangelicals are only starting to accept the idea. A common fear is that supporting people with HIV condones sinful behavior. Kay Warren tells them, 'It's not a sin to be sick.

In her book Warren describes her travels to Mozambique, Cambodia, the Philippines, Rwanda, and elsewhere to meet AIDS orphans and women who got HIV from unfaithful husbands and to learn of the vulnerability of child prostitutes. The majority of people with HIV worldwide are women.

'If people are infected, they need to be embraced and valued and to receive the love of relationship in the church,' Warren said in an interview, wearing an AIDS red-ribbon lapel pin wrapped around a cross. 'Churches can reduce the stigma.'

A small number of detractors have also focused on the Warrens' willingness to invite abortion rights supporters--Sen. Barack Obama in 2006 and Sen. Hillary Clinton in 2007--to participate in the AIDS summit. The Warrens, who avoid partisan politics, had invited every presidential candidate. Only Clinton attended, while others sent videotaped messages.

Not everyone welcomes the support of conservative Christians. Gay activists, who for years waged a lonely, difficult struggle to help the HIV-infected, have been suspicious. Many wonder whether evangelicals are 'coming in looking for Christian scalps,' Haas says.

Warren writes that she understands the concern 'when we show up 25 years later and tell them we would like to serve them.' But she says she is building relationships with gay-led AIDS organizations. Haas says pastors who travel overseas with World Vision often start AIDS ministries in their own neighborhoods.

'I think we had to earn our stripes,' Warren says. 'Some immediately embrace us. Others wonder if this is the cause of the month. Others are fearful and suspect we have hidden agendas.'

Beyond providing care, the Warrens have also entered the contentious policy debate over how to end the pandemic. They have developed an approach--which they've copyrighted so that it cannot be misrepresented or misused, they say--called SLOW/STOP. It is a complicated acronym: To slow the spread of HIV, they support correctly using condoms, limiting the number of partners, offering needle exchange--even though Kay Warren says it's still not clear how effective that is--and waiting for sex. 'I don't know how anyone can reasonably say that virginity isn't a protection against HIV,' she says.

To stop the virus, the Warrens advocate saving sex for marriage, teaching men and boys to respect women and girls, offering treatment through churches, and partnering with one person for life.

Kay Warren says that while the U.S. government can make the issue a national priority and businesses can fund charity work, the church can be especially successful in easing the crisis by promoting behavioral change. In Dangerous Surrender she aims to break down barriers that have kept conservative Christians away from the issue.

'I hope this book is disturbing to people,' Warren says. 'There are situations in the world that I cannot tolerate for one more second.'