Facebook HQ

“In addition to the explicit gender-targeting, Facebook also offers advertisers the ability to use what it calls “Lookalike Targeting,” which allows advertisers to target customers with traits similar to those of their customer base. To understand why this is problematic in the employment context, consider a company with an all-white workforce, which decided to recruit and hire only applicants that “look like” their current workforce. Such a hiring strategy would plainly perpetuate the exclusion of workers of color, violating laws, including Title VII, that prohibit employment practices that have a discriminatory effect”.

Source : How Facebook Is Giving Sex Discrimination in Employment Ads a New Life | American Civil Liberties Union