Long the heart of the home-schooling movement, conservative evangelicals are cheering a new Department of Education report that shows the number of home-schooled students has surged by 74 percent over the past eight years, to 1.5 million.

"As a homeschooling parent myself, I understand the desire to give children an environment that affirms traditional values," Tony Perkins, president of the Family Research Council, wrote in an E-mail to supporters this week. "The government has eliminated God from the classroom and too often replaced Him with an anti-life, anti-family curriculum that misses life's deepest meaning."

The Department of Education report, which finds that 83 percent of home-schooled students' parents cite "providing religious or moral instruction" as one reason that they home-school—up from 72 percent who said so in a 2003 survey—would seem to suggest that evangelicals could be responsible for much of the growth in the movement.

But experts say that the home-schooling scene is diversifying and that the evangelical share of the movement is actually shrinking.

"We're seeing an increase in the number of families that might cite moral and religious instruction as one factor but not the overriding one," says Ian Slatter, spokesman for the Homeschool Legal Defense Association, a Christian-led advocacy group. The association estimates that evangelicals account for just over half of home-schooling households today, down from about two thirds in 2000.

In one sign of that growing diversification, membership in the Homeschool Legal Defense Association has grown by 42 percent in the last decade, to about 85,000, while the number of home-schooling families has grown at a much faster rate.

According to the Department of Education report, released in late December, 36 percent of home-schooling parents reported that providing religious or moral instruction as the most important reason behind their decision, followed by "concern about the school environment" (21 percent) and "dissatisfaction with the academic instruction available at other schools" (17 percent). Because previous surveys didn't ask about the most important factor in the decision to home-school, it's impossible to know if more or fewer parents are citing morals and religion as the primary reason.

The report did not ask home-schooling parents about their religious affiliation. The Department of Education is planning to release a more detailed report on the demographics of home-schoolers later this year that will include such factors as race and income level, but the DOE doesn't ask questions about religious affiliation, according to Gail Mulligan, a project officer at the National Center for Education Statistics.

Brian Ray, president of the National Home Education Research Institute, says recent studies suggest that evangelicals still account for roughly 70 percent of home-schooling families. But the picture has changed dramatically since the 1980s, when conservative Christians launched the movement, he says. "In the early years, you had to be a pretty big believer in something to home-school because there was a lot of adult peer pressure not to do it," he says. "There are a lot of people who now consider home-schooling who would have never 10 or 15 years ago."

The National Home Education Research Institute, which supports home schooling, puts the number of home-schooled students above the Department of Education's estimates, at just over 2 million. The institute's research has found that home-schooled students score about 15 to 30 percentile points above their public-school peers on standardized achievement tests.