Gender discrimination by an employer may not be legally justified by the argument that other employees, or customers of the employer, would prefer to work only with employees of one gender. The only exception to this general rule is a situation where the gender of the employee is an integral part of the service being offered by the employer.
Example: A nightclub catering to a male, heterosexual clientele requiring that exotic dancers be females.
The legal theory under which this type of gender-discrimination case would be raised is disparate treatment.