2013-11-05. Our new study shows that your choice of Regular Coke vs. Coke Zero vs. Diet Coke may depend on the testosterone which you were exposed to before you were born. The pre-birth testosterone is indicated in your “digit ratio”, the ratio of the length of your index and ring fingers. Our study demonstrates that a higher digit ratio leads to a higher likelihood to purchase Diet Coke and Coke Zero (over Regular Coke).




FIGURE 1.  Male Consumers’ Choice Shares by Low vs. High Digit Ratio


Panel A: Choice of Gender-Imaged Products



Panel B: Usage of Gender-Imaged Clothing Colors



Note. The figures depict which Cola beverage the field study participants chose (Panel A), and which colors they wore in their clothing (Panel B). Digit Ratio is the ratio of the length of one’s index finger and ring finger, and it has been shown to be an indicator of people’s prenatal testosterone exposure. The Figures contrast the choices of study participants who had a low (masculine) digit ratio, versus participants who had a high (feminine) digit ratio.


The full study is available as follows: 

Aspara, Jaakko, & Van Den Bergh, Bram, "Naturally Designed for Masculinity vs. Femininity? Prenatal Testosterone Predicts Male Consumers' Choices of Gender-Imaged Products", International Journal of Research in Marketing, Forthcoming. Available at:




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