EN: This New Scientist article summarizes a publication  about the correlation of oestrogen level and facial attractiveness of women. The study claims that women are most attractive at the highest point of oestrogen concentration. This makes complete senses as at this time the ovulation takes places and mating should be done (at least in nature :)).
 Facial appearance is a cue to oestrogen levels in women. M.J. Law Smith et al., Proceedings: Biological Sciences, 2005, (DOI: 10.1098/rspb.2005.3296)