I think the jam bands in general are off the list for me I totally get the rationale but usually jam bands come with other contextual aspects (chillnes, substances, etc) which can be sexy and there's at least a reasonable gender balance there. I may be biased on this one as an oddly high number of women I've been attracted to have been into the jam band scene.
I think there is also some difference between gender balance of fans and sexiness of the band. Like... The Trans Siberian Orchestra has a fairly even gender balance but is like anti Viagra.