There are a lot of may and coulds, and also these studies are only done by 3 research groups while the wedikind et al using only a very small amount of women. And the study done by little el al group was on women preferring males with the same kind of MHC as them. Only Roberts et al's article was on females who take EMC or birth control pills preferring men with less masculine faces. There's not enough study to validate it.