From the WSJ:

"Despite notching significant gains in the legal world, female law-firm partners continue to lag behind their male counterparts when it comes to billing rates, commanding on average 10% less for their services, according to a new analysis of $3.4 billion in legal work.

The gap begins at the junior lawyer level, and is more pronounced among seasoned attorneys at major firms, persisting even when partners possess similar levels of experience and work in the same market, according to the review by Sky Analytics Inc., a provider of software to help companies track legal spending and invoices." (link)

Here in New York:

[T]he average male partner at a 1,000-plus lawyer firm with 13 to 24 years of experience representing investment banks was billed out at about $679 an hour, nearly 25% more than the average female partner, whose rate was $544." (link)

And as to upward advancement:

"Women make up only 17% of so-called equity partners with ownership stakes at the 200 top-grossing U.S. law firms, according to the National Association of Women Lawyers, and they are similarly underrepresented in management roles and on powerful governing committees." (link)

These number are far from encouraging.