How? If a nickname singles out an employee in a legally protected category, a court may say the nickname contributes to creating discrimination or an illegal "hostile environment."
That may seem obvious in such cases as referring to racial minorities in disparaging terms. But singling out female employees with nicknames, especially pregnant ones, can be legally dangerous.
Example: After congratulating a sales rep for her good performance, a manager said, "You're not going to go and get pregnant now, are you?" The employee did become pregnant the following month. When the manager found out, he stopped calling her by her name and started calling her "prego." He also started yelling at her about her work.
The employee filed a sex- and pregnancy-discrimination lawsuit. The court sent the case to trial, saying that calling her "prego" was similar to using a racial epithet and that it created a hostile environment.