When a married supervisor conducts longstanding, concurrent affairs with three female subordinates at work and grants them professional favors over more deserving candidates, does it constitute unlawful sexual harassment?
In Miller v. Department of Corrections, the California Supreme Court has held that it does, despite a longstanding reluctance by courts to recognize claims of so-called "sexual favoritism."

The case was brought by two former employees at the Valley State Prison for Women (VSPW). The Plaintiffs alleged that they were subjected to discrimination and harassment as a result of the chief deputy prison warden's multiple workplace affairs.

The crux of the complaint is its allegation that the deputy warden openly carried on three affairs with female employees at the prison, all subordinate to him, and granted those women undeserved privileges and promotions because of his relationship with them. At the same time, the suit alleges, female employees who complained about these relationships were punished, and retaliated against, for their objections.

One might contend that they have been denied access to job benefits not because of their sex, but because the boss happened to choose a different woman to have an affair with. The EEOC's Policy Guidance states the agency's position on when sexual favoritism constitutes illegal harassment or discrimination. It recognizes the possibility that widespread favoritism can create a hostile environment for both male and female employees.
The Court said, “when such sexual favoritism in a workplace is sufficiently widespread it may create an actionable hostile work environment in which the demeaning message is conveyed to female employees that they are viewed by management as 'sexual playthings' or that the way required for women to get ahead in the workplace is by engaging in sexual conduct with their supervisors or management.”

Isolated incidences of sexual favoritism, while clearly inappropriate, are not considered unlawful by the EEOC. The safe thing, then, for employers to do is prohibit such favoritism, just as they often have policies banning nepotism.
When sexual favoritism is as pervasive and unfettered as it is alleged to have been at VSPW, no woman can get a fair evaluation based on her abilities and work-related talents. That is the essence of sex discrimination, and the Miller court was right to put a stop to it.