Second-to-fourth digit ratio (2D:4D), a widely studied putative marker for 
masculinization through prenatal androgen exposure, is lower (more masculinized) 
in athletes than in general population controls, and athletes with lower 2D:4D 
have higher sporting success. Occupations differ markedly in perceived 
masculinity and actual maleness (sex ratios), but these givens have not yet been 
picked up and utilized in 2D:4D research. Accordingly, this study extended 
existing accounts on 2D:4D in athletes to a novel approach: 2D:4D and possible 
relationships to a variety of candidate variables (demographic, 
fertility-related, psychological, and other) were investigated in firefighters, 
a highly male-dominated occupation. Contrary to expectation, 2D:4D in 
firefighters (N = 134) was not lower than in local male population controls. 
Lower 2D:4D corresponded to lower service ranks. Replicating previous findings 
either unequivocally or partly, lower 2D:4D was associated with larger family 
size, later sibling position, left-handedness, and higher scores in the 
disinhibition component of sensation seeking. Not replicating prior evidence, 
2D:4D was unrelated to body-mass index, offspring sex ratio, and sporting 
performance level. Novel findings included low 2D:4D in those with low 
relationship satisfaction and in cigarette smokers, especially among heavy 
smokers. Absolute finger length, a positive correlate of pubertal-adolescent 
androgen levels, was also considered. This marker showed negative associations 
with relationship consensus and satisfaction and positive ones with perceived 
quality of relationship alternatives and the experience seeking component of 
sensation seeking. The merits of this additional marker, relative to 2D:4D, for 
supplementing studies of possible sex-hormonal effects on personality and 
directions for future inquiry along these lines are discussed.