There's a prof I know at the medical school I'm at that's doing hormone studies with the jet fuel that military aviators are exposed to ... apparently it's got an exceptionally high affinity to estrogen receptors ... but while it blocks endogenous estrogen from binding, it's actually got much stronger estrogenic properties. This of course is bad bad news for any male pilots ... uless they're interested in having a nice set of knockers on their own chest and no sex drive.