Facebook's ad options could be discriminatory

Facebook reportedly allows advertisers to target certain groups illegally.

An ad customization option called Ethnic Affinities lets advertisers target specific groups - or exclude them.

Citing a ProPublica report, CNNMoney wrote the tool can be used to discriminate against users with housing-related ads. That's forbidden under the Fair Housing Act.

While Facebook doesn't directly ask users for their race, the massive amounts of data it collects can infer it.

Christian Martinez, head of multicultural at Facebook, defended the use of ad targeting based on Ethnic Affinities in a blog post published after the ProPublica report.

"Everyone benefits from access to content that's more relevant to them. But this is especially critical for people who choose to affiliate with ethnic communities," he wrote.

Read more from CNNMoney.