The glass ceiling: law edition

When the New York Times talks about the issue of women and the workplace, it's usually in the form of patronizing articles about the supposed "opt-out" revolution, or some piece of sexist idiocy on the op-ed page. But today they actually have an interesting and relevant
piece on the under-representation of women at the highest levels of prestigious law firms:

Although the nation's law schools for years have been graduating classes that are almost evenly split between men and women, and although firms are absorbing new associates in numbers that largely reflect that balance, something unusual happens to most women after they begin to climb into the upper tiers of law firms. They disappear.

Their attention is still fixed firmly on the upper-middle-class and wealthy, but at least they acknowledge the reality of discrimination. Or something; you try to parse the following quotation:

"Firms want women to stay. Men at the firms want women to stay, and women want to stay. So why aren't they?" asks Karen M. Lockwood, a partner at Howrey in Washington. "Law firms are way beyond discrimination — this is about advancement and retention. Problems with advancement and retention are grounded in biases, not discrimination."