In fact the very fact that some women have an abundance of EWCM whilst others don't have any to note further highlights how different we all are 'down there'!
It would be interesting to do a survey on women who have had children to see if there is any correlation between amount of EWCM and also perhaps how much seminal (think that's how it's spelt, the sperm travel fluid) fluid the men have and the resulting gender. Both my husband and I seem very fertile in this respect... Sorry if that was an over share! I know with so many other (and much more likely) swaying factors the results would probably not be very conclusive but might show some significance. Just a thought to test some of these theories. Diet I should imagine is a much harder theory to prove retrospectively as its so diverse.