Yeah, it would be just great to make teenagers take a test before having sex. Like you said, they have to take one to drive a car...
Oh, wait! Let's not forget all the teenagers that drive without a license, or drive during times or under conditions in which their license isn't viable. And the teenagers who passed the test and got a license, and then had an accident because of reckless driving!
A test will not solve anything. Neither will a contract. Both can be ignored in the heat of the moment. You want to stop teenagers from having premarital sex? Get the government to pass a law requiring chastity belts (male and female) to be worn from the start of school until the honeymoon. That's the only chance you have of it working! And we all know, that will never, ever happen.
And by the way, a lot of teenagers do have this discussion before sex. I did, with every partner i've had. And you want to know a secret?? Most of the time, we still didn't use protection. We didn't want a baby, and we had no way of taking care of one. But when your making out and getting naked, you don't want to be the one to say "oh, crap, we gotta stop! I ran out of condoms!!"
daile