Which fallacy does this argument contain?
You shouldn't let your teenage son get his driving license. Before long, he will be driving rashly and breaking all the traffic rules.
This should be the slippery slope fallacy because it implies that if the person lets a person get a driving license, it is guaranteed that the person will soon drive rashly and break rules just because of their age. Breaking rules occurs even with non teens and being a teen is not a cause of that.