“Ugly” and “attractive” are subjective characteristics assigned by HUMANS. They have nothing whatsoever to do with physiology.
I call BS on this and want to know what the author looks like. Sounds like he is using his grant dollars to troll for chicks.
the biggest one is symmetry. both sides of the face are the same. the next is proportion, alignment, good hip ratios, etc... if an individual has these attributes, they are more likely to be what we call "attractive."