I'm never for doing anything halfway. So if you want your kids to leave the church when they leave your home, I've got a list for you. Here are four ways that you can contribute to your child's spiritual demise:
1. Make other things a priority over church assemblies and functions. Be sure that you are giving your child the impression that there are some things that are more important than assembling with the church if they are "big" enough. Be sure the church comes second to some things. These things include (but are not limited to) sporting events, vacations, family get-togethers, and even some forms of working. Only doing this occasionally is sufficient to get the point across to your child. Better yet, cut out Bible class entirely and only come for Sunday morning worship.
2. Don't talk about God, Jesus, or the church when you are at home or in the car. Keep your lips sealed when it comes to spiritual matters. Don't ask, and don't tell.
3. When you do talk, be sure to complain and nitpick as much as possible. Complain about the preacher, his sermons, the elders, the deacons, the singing, the song selection, the Bible class, the Bible class teacher, the Bible class materials, young kids, older people, and any other Christian who is different from yourself. Never give your child the impression that you are appreciative of the church, or that you respect those who serve it. Never be satisfied. Be sure to plant the seed of dissatisfaction in your child's mind.
4. Indulge your child's immaturity. Despite the fact that they have yet to develop a real concept of the value of a dollar, give them full control when it comes to their most valuable asset: their soul. Even though they might want to eat pizza and french fries for every meal, let them make every soul-affecting decision for themselves. If they don't want to do "it", don't make them do "it." This applies to all aspects of participation, including Bible class, worship, and even (for the boys) leading worship. Make attendance optional. For that matter, make everything optional, with no consequences.
Of course no Christian parent really wants to drive their child away from God and the church. But sometimes we do things that might inadvertently do just that.
I'm not saying that if you ever do one of the previous four things I mentioned that your kids are destined for Hell's fire. But what I am saying is that if you can catch yourself before you keep up some of those pitfalls then you will have a far better time helping your children to transition from being preteens, to being spiritually minded teenagers, and then to being faithful Christian adults.