Gentlemen, be advised (if it’s not already too late) that you may be able to influence your chances of going bald. The authors of this study compared the patterns of baldness in 92 pairs of identical twins and correlated these with the results of a lifestyle questionnaire and testosterone levels. The findings differ according to the area of hair loss. For the frontal region, smoking and the presence of dandruff are significant contributors; for the temporal region, prolonged exercise and alcohol consumption were associated with thinning hair, whereas daily hat use, high BMI and high testosterone were associated with a reduction in hair loss. Thinning at the crown was associated with smoking, prolonged exercise and stress and with either alcohol abstinence or consumption of more than four units per week (you can’t win on that one). In addition, lower BMI, having more children, increased caffeine intake, alcohol abstinence and a history of skin diseases were all significantly associated with thinning.