It's rather interesting. You have to enable JavaScript. It's not a security breach; although, I think it's surprising that JavaScript is able to iterate through a list of sites and tell what ones you've visited by checking the CSS colors... isn't that a frightening thought?
My results were of unquestionable certainty!
Likelihood of you being FEMALE is 0%
Likelihood of you being MALE is 100%
Site Male-Female Ratio
google.com 0.98
myspace.com 0.74
youtube.com 1
microsoft.com 1.08
amazon.com 0.9
walmart.com 0.77
download.com 1.27
digg.com 1.56
sing365.com 0.89
staples.com 0.98
newegg.com 2.23
filefront.com 1.63
sun.com 1.04
nintendo.com 0.9
petsmart.com 0.59
intel.com 1.78
wowwiki.com 1.38
actiontrip.com 1.2
icq.com 0.8
mozilla.org 1.33
worldofwarcraft.com 1.08
drsfostersmith.com 0.54
divx.com 1.99
creative.com 1.53
slashdot.org 1.74
thottbot.com 1.35
joystiq.com 1.44
blizzard.com 1.25
nmsu.edu 0.94
recaptcha.net 1.15
oreilly.com 1.67
curse.com 1.99
stickam.com 1.15
w3schools.com 1.27
I think the reason for this is due in no small part that geekier sites tend to be more likely to have male visitors. I guess the fact that I visit Slashdot regularly might be a pretty strong implication... (Newegg is also HIGHLY male, which I found interesting...)
Now, I do think that sometimes the implications of inspecting history isn't entirely the best method of determining the gender of a visitor (it's a good start, though). Especially since I only visited ICQ to check their support page for a friend (I don't use ICQ). Same thing for a few other sites--I wound up there simply from clicking links.