Schienle et al. (2005) used fMRI to examine fear and disgust elicited with images in male and female subjects. Self-report measures indicated that they had induced the appropriate emotions, with women had responding more strongly, although brain activation showed stronger reaction in men for fear stimuli. No gender differences in activation were reported for the disgust stimuli. Neither Shapira et al. (2003) nor Moll et al. (2005) found any gender differences in their fMRI studies of disgust, either.
There is a gender stereotype that men (and especially boys) have a higher tolerance for disgust than women (and especially girls). However, it appears there are not neural differences in their experiences of disgust. Widen and Russell's 2002 study of preschoolers may shed some light on the social difference. In an experiment where 80 preschoolers were asked to identify the emotions of fictional children in a story, boys were more likely to describe a male character as "disgusted" or "grossed out" whereas girls were more likely to describe a female character as "afraid." This suggests that there may be a reciprocal relationship between fear and disgust, where responding to something as "gross" robs it of some of its fear-inducing power. However, this theory does not seem to play out in studies of phobia, such as De Jong et al's 1997 study on spider phobia, which showed strong positive correlations between fear and disgust responses. However, De Jong et al only studied girls and their mothers, so the relationship between fear and disgust may be different for males.
My experience of the emotion of disgust certainly has a lot in common with the physical sensations I associate with fear: the tightness in my stomach, the tendency to avoid looking directly at the stimulus, and the inability to ignore it. It's worth noting that of all the phobias, the one that is equally balanced between men and women is the blood/needle phobia -- which I never had any problem with before started testosterone. My hormones are administered by intramuscular injection, which I do myself on a weekly basis. As with many of my psychological changes, it's impossible to know the root causes, but my reaction to doing my injections has gotten worse over time, rather than better. I've luckily only had one actual fainting episode, and some weeks I do better than others, but on the whole, it feels like it's getting worse. I expect this has more to do with increased experience with needles than hormonal levels, but in general, exposure reduces phobic reactions, so my increased dread of needles strikes me as especially curious.