First, Sandy,

I totally agree with you - the few men who
use negative locker room talk about women have
caused the downfall of many women in management.
The majority of men don't make statements like this,
but they do let them be discussed.
So good guys, stop being a part of the problem.  Tell the
insecure guys to shut up, that nobody wants to hear that
stuff anymore.

Second, Miguel,

Thank you for pointing out that the gender gap
exists all over the world.

You propose the Wikipedia site itself might be a problem,
because women don't want to work with it because
it isn't WYSIWYG.  <*sigh*>
The reasons being:

1. "men are a bit more obsessive in their work than women"
2. "maybe it's the look of the site, not attractive enough" 
3. "women tend to focus their attention on people, instead of things, as men do"

#1 & #3 have been stated about women and work for over a century.

#2 --> Has a woman *actually* told you that she won't post to
Wikipedia because she finds the interface too difficult?
You're proposing that women don't want to post as experts
because they don't want to be an expert in using a complex interface.
Because of a deficiency with women, they don't want to become
experts with a system that would allow them to post their
expert opinion.
I sense a catch-22 argument here.
Reworking the Wikipedia interface is not really addressing the problem.

Another reason why "women don't want to ____ because ______"
We should have a Wiki page on these bizarre reasons.
If we put them in a long list it might not help anyone, but
it might be humorous.  We could just refer to reason #1054
or #782 or #11659 with links to the Wiki page.  Good for
a laugh.  Women could post any new funnies, like "women
aren't as obsessive about their work as men are".
This might become the most popular set of pages on Wikipedia.
Of course, it would probably attract trolls. So let's not.

To have a serious response to the problem, let's have a
'Women Post to Wiki' month, and have a banner
about it on every Wiki page during the month.  It validates that
the world community accepts women as experts, and invites
women to post who may have thought about it before, but didn't.
I love that Google has different logos every day. Wiki
can have a different logo for that month.

- Susan Spencer Conklin