Most English-speaking countries tend to characterize "feminine" handwriting as neat, even, round, small, ornate and symmetrical, while handwriting assumed to be "masculine" often gets described as hurried, uneven, messy, spiky, sloping and bold. One comparative study in another language (Hamid 1996) suggests that some of these stereotypes cross over into other cultures and writing systems.
One early study (Lester 1977) examined "males who write with handwriting judged to be feminine and vice versa" and concluded their handwriting "is not reliably associated in these studies with femininity or with sexual orientation." However, later studies have suggested that most people can discern a writer's sex with better than chance accuracy. One study of handwriting specimens from 73 men and 168 women (Sappington 2003) found a mean handwriting tidiness score for men was 1.8 and 2.8 for women, a significant difference of 1 point on a 5-point scale: "Masculine Gender Role predicted sloppy penmanship and Feminine Gender Role predicted tidy writing, independent of the writers' biological sex." Another study (Hayes 1996) found students were able to discern writer sex at the 75% accuracy level even with small amounts of material, sometimes only a single letter or a single geometric pattern: "It was suggested that sex or gender is present in handwriting in much the same way as it is present in movement of the whole body."
It is interesting that there are many outward expressions of our inner selves, not limited to our manner of dressing, but also including our choice of language, our gait, and our responses to different sorts of events. This type of thing seems to be curiously fascinating, yet simultaneously extremely threatening to a certain subset of people. It is currently highly un-politically correct to entertain any ideas that we may, in fact, be influenced by anything other than our environment and our socio-economic status. When the idea of digit ratio as an indicator of behavior and sexual orientation became a craze in the gay community after it was introduced on an episode of the "L Word" television show, it also was blasted by other segments of the lesbian community, as in this commentary for the blog True/Slant. The fact is that studies show trends, correlations, and patterns, and they can be highly useful in the analysis of the aggregate, but it is more complicated to apply these finding from large groups to individuals. Still, I have found self exploration of these topics has rather been liberating and freeing, as it has confirmed what I already have known about myself, but which society denied.