This type of sexual harassment can occur between a superior and a subordinate, as well as, between co-workers, an example would be unwelcomed sexual jokes, slurs, and innuendoes. An assessment is made based upon the totality of the circumstances. No one factor controls the overall outcome. Generally, an employee must complain to the employer about sexual harassment. To establish an employer's liability, the employee generally has to prove that the employer know of the sexual harassment and failed to take appropriate remedial action.
Sexual harassment is about the abuse of power.
It is not about sex. It is not about romance. In our society, power is derived from many sources. The ability to hire and fire others creates power, as does giving grades and recommendations, making job assignments, and evaluating someone else's job performance. Being of a greater physical size than another person also creates power.