Okay, one more time.
There are no laws in any state regarding DATING. Any minor of any age can date anyone of any age that his or her parents agree to allow him or her to date.
There are lots and lots and lots of laws regarding when a minor can and cannot have sex.
So it depends on your definition of dating. If by dating you mean go to school functions, hang out at the mall, catch an occasional movie, that's fine, no problem. As long as the 14 year old's mommy and daddy say it's okay, it's okay. (If they say it's not okay, then your "friend" had better find another place to spend his time because mommy and daddy will ALWAYS win - and the law will ALWAYS back them up).
If by dating you mean any kind of sexual contact (NOT limited to intercourse) then yes, illegal, big time.