Chris Blake, account director at MSR Communications, remembers it like it was yesterday.

Mary Shank Rockman, the principal at MSR, had just announced she was pregnant, a week after Blake's wife announced her pregnancy. Blake and Rockman were two-thirds of a boutique agency in San Francisco. That day, Rockman was on the phone with more news: the agency's biggest client was leaving after four years.

"Our office was a flat and my desk was in the kitchen," Blake recalls. "I was ...