Editors’ Note: This article was originally published in June 2009.

Q: Like many New York law firms, we seek to recruit and retain women attorneys and specifically would like to increase their number within our partnership ranks. Although women are well represented in our junior and mid-level associate classes, the numbers decrease and change dramatically at the partnership level.

Considering the number who make up our entering classes, we think our partnership numbers should be much higher. What should we do to increase the number of women associates who stay and become partner?

A: There isn’t a magic wand, but one thing is clear: It’s absolutely crucial for law firms to possess leadership that understands the vital importance of natural, informal mentoring and are prepared to provide platforms that teach techniques for mentoring across differences.

Marissa C. Wesely, a partner at Simpson Thacher & Bartlett, is one such industry leader. Not only is Wesely a highly regarded corporate attorney, but she also is an extraordinary woman who boasts an outstanding track record of ensuring that women associates have fair and meaningful access to partnership opportunities.

First, Wesely reminds us that we have come a long, long way ladies (and gents). During the last five years the pace of change has accelerated.

In 2006, women represented 29.1 percent of new equity partners. While encouraging, this percentage should not make us complacent. With nearly 50 percent of law school graduate classes consisting of women, Wesely concedes that many in the legal industry simply figured that greater associate numbers would yield significantly greater women partners. But when the overall percentage of women partners still hovers around a steady 17 percent, it becomes apparent that more than mass is needed.

In order to retain greater numbers of women associates, Wesely emphasizes that there are many pieces to the puzzle, the biggest and possibly the most challenging being finding natural mentors.

Formal mentoring programs are effective mechanisms for introducing the skills necessary for developing networks and maintaining connections. But the pot of gold lies in the informal, natural mentoring relationships that provide the esoteric nuances that help transform women associates into partners.

While it sounds simple enough, Wesely acknowledges that the process is riddled with complexities, since barriers exist to mentoring across differences. Simply stated, people feel more comfortable with people with whom they share similarities, and may even possess unconscious biases against those they perceive as different. A convergence of these dynamics serves to stifle the development of informal mentoring between men and women and thus diminishes opportunities for women associates to access key partnership track development.

Law firms that wish to retain talented women associates should give serious consideration to developing best practices and training programs that focus on mentoring across differences, especially when the leadership of the firm is mostly white and male. Women associates who want to become partners need to learn how to be mentored across differences and be prepared to develop a team of internal and external mentors.

In an increasingly global economy, Wesely stresses that it is of paramount business importance that diversity of all kinds be represented in law firm leadership. Women partners in particular bring different world views many of which can help diffuse the “locker room” mentality that can emerge when homogenous male leadership controls the message delivered to clients.

Law firm excellence demands that women partners be at the table. Not one, not two and not 17 percent. Yes, we’ve come a long way baby, but, the journey continues.

Katherine Frink-Hamlett, a graduate of New York University School of Law, is president of Frink-Hamlett Legal Solutions Inc.