Christine Tsien Silvers says perfectionism runs in her family. Her mother, a detail-oriented computer scientist, emigrated from China to Minnesota and was "always taking classes to get a better job."

She earned a Ph.D. from MIT and an M.D. from Harvard. "But I also wanted to be the best mother possible," says Dr. Silvers, so she worked part-time, not full-time, emergency-room shifts to maximize her time with her children, ages 3, 5 and 8.

Dr....