As people have said it depends on the ages of people involved. 18 and 14? Wrong. Illegal. Sick.
24 and 20? fine.

Until you're an adult its a huge difference. Think of it this way, would YOU date someone four years younger than you? Kinda gross huh?

This is the second time you've started a thread like this in about a month. It's still wrong for an adult to date a child.