Facebook admits a level of bias in that people are "shown ads they may be interested in". [Source: BBC]
Facebook has been accused of breaking equality law in the way it handles job adverts.
Campaign group Global Witness said it failed to prevent discriminatory targeting of ads and its algorithm was biased in choosing who would see them.
In an experiment, almost all Facebook users shown adverts for mechanics were men, while ads for nursery nurses were seen almost exclusively by women.
Facebook says its system shows people ads they may be most interested in.
The social-media giant approved both ads for publication, although it did ask the organisation to tick a box saying it would not discriminate against these groups.
Global Witness pulled the adverts before they were published.
