TLDR; I wouldn't know where to start excluding cultural bias when conducting such a study. Facial hair is 'hip' among younger men since about a decade now. Ma

TLDR; I wouldn't know where to start excluding cultural bias when conducting such a study. Facial hair is 'hip' among younger men since about a decade now. Marketing, advertisements, etc. are all biased in the amount of men they display, commonly models, wearing facial hair for this reason. Then you have countries, particularly those with a Muslim majority, where facial hair for men is worn for cultural/religious reasons. Many parts of Latin America are heavy on mustaches compared to the 'West', etc., etc. I.e., move on; nothing of value to extract from this study.