Cycling with children has to be one of the most rewarding experiences that I have ever had. I have cycled with both my boys (24, 21) when they were teens; my youngest rode XC with me twice (when he was 13 and 17). I would encourage everyone to ride with children whether or not they are yours.
My experiences have been so enriching, I have been riding with teens since 1998. I now run a non-profit that uses cycling to help kids set and reach goals, teach life skills, promote teamwork and an appreciation of diversity, help others through service projects, and promote environmental awareness.
Check us out at http://www.biketernity.org
and join us!
If I can help anyone with questions about cycling with teens I would love the discussion.