Representation - What does it mean?

I was reading this article in the Los Angeles Times (Women at Risk) and it reminded me of the age-old debate over the meaning of representation.

Is someone representative by definition?  In other words, because the voters choose a candidate as their "representative", does that mean that the chosen individual will automatically be representative of them?  Or is it also important to expect that our legislative bodies look like us?  Does it matter that women now hold 90 seats in Congress, which is nowhere close to the proportion of women in the population?  Does it matter that women may hold even fewer seats after the November elections?

What does it mean to say that our legislative bodies should be representative of us?  We are a republic, after all, and decision-makers are expected to represent us in their decisions.  Would it make a difference if our Congress were made up of 250 women rather than 90 women?  How would Congress be different?  In its rules?  Its demeanor?  Its decision-making processes?  Or would the culture of Congress take over any gender-based (and well-documented) sociological tendencies?

This article mentions Jeannette Rankin, a woman whom I've long found to be a fascinating story.  She was elected to Congress as a Republican from Montana BEFORE the 19th amendment was added to the Constitution giving all women the right to vote.  And she is also noteworthy for having voted against U.S. entry into the Great War (World War I) as well as U.S. entry into the Good War (World War II).  Here's some information about Jeannette Rankin (Women's History) and here's one of her most famous quotes:  "You can no more win a war than you can win an earthquake."