Home schooling started as a trend among well-educatied Christian conservatives who wanted to give their children a faith-based education, according to published reports. Now it has spread to other groups, including transient military families... Some parents coordinate with other home-schooling families for field trips, recess at the local park or swim lessons. They also share lesson plans, resources and expertise. That usually means parents control their children's social lives and the children have fewer authority figures in their lives, says Mitchell Stevens, assistant sociology professor at Hamilton College in upstate New York. He wrote a book about home-schooling trends, "Kingdom of Children," which is scheduled to hit stores next spring.