I hope you're considering a restriction to parents and married (or have been married) members. Sometimes I'm asking questions of other parents, or I'm in a thread that is, and a teenager chimes in. I mean no offense to them, but one's perspective on parenting issues changes dramatically when you become a parent. This is true with marriage as well.
I haven't had any difficulties with this per se personally, but I really don't believe a teenager is qualified to provide feedback on parenting. I certainly would have offered different advice on the matter when I was 17.
Also, as with any advice forum, I hate to see someone's request for feedback turn into a theological debate. Sometimes someone's take on scripture applies to the person's question, but sometimes the thread gets hijacked by people who turn the whole direction of it. I would hate to have an honest question turn into a battle between a few other people that takes my question off the table.
No offense to my teenage friends/members. Just sayin'