(For purposes of clarification, I'm talking about positive outcomes from a male and a female being involved in an exclusive, romantic relationship. I'm assuming that they are too young to get married within the next few years; if they intend to get married soon, then this may not apply.)
So here's the list:
Well, I never made it past number 1. The reason for this is not lack of thought. In fact, I've pondered this issue quite a bit. I simply don't see any positive outcomes from dating while in high school. It may seem fun at the time, but the end result is usually heartache or worse for at least one of the parties involved.
More importantly, dating is nowhere modeled for us in scripture. When we look at the broad picture of what God wants from His followers, He gives some of them the joy of marriage. Others He blesses with singleness. Nowhere does God sanction or even hint at approving of multiple dating-style relationships.
Dating is a modern, secular idea. Of course society will embrace it. What is problematic is that so many Christians approve of and get involved in dating relationships without giving any thought to whether or not God approves of it.
Dating is a train wreck waiting to happen. The younger the people involved, the worse the problems. Let's say two Christian teens begin dating at age fifteen. Maybe they really like each other. Maybe they would even like to get married. The problem is that they are now "all dressed up with nowhere to go." They probably have intense feelings for one another that are very real. They may want to get married (with all that involves). However, unless they plan to get married soon, they will end up frustrated, tempted, or worse.
I implore you. Please think through the problems dating brings. The good is minimal at best, while the bad can be hugely devastating.
Let's try our best to think what God thinks about dating. Wait until you are old enough to marry, then ask God to find someone godly to be your spouse. Court that person, get married, and rejoice in Christ.