At many schools, there are no formal rules about professors dating students. It is discouraged, but not prohibited. For most educators, there is an unwritten rule that getting involved with students is a bad idea. It is usually suggested that no professor should date a student in his class.

Is it illegal to sleep with a lecturer?

While legal, it is hardly professional for lecturers to date students. Professors are required to alert the university should a relationship develop between them and a student to ensure no unfair advantage is given to the student.