We plan to implement this feature but we need more info on which ethnicity groups you expect to get from our API. If you vote for this feature, please write a comment about that.versae commented
Ethnicity can be delicate and difficult to estimate, maybe skin tone, based on for example Von Luschan's chromatic scale (http://en.wikipedia.org/wiki/Von_Luschan%27s_chromatic_scale), is a better idea, taking into account the difficulty of calculate the skin tone depending on the light in the picture.
7 votesversae commented
Cheekbones as well as jaw would be nice