As Phil notes below , "it's become standardpractice" at many large law firms "to offer reduced-work schedules and pay for parents (bothmothers and fathers) who want to spend more time at home with theiryoung children. And while such arrangements can slow associates in thequest to make partner, they don't derail them entirely (the way theyused to)."
I'm neither a parent nor at a law firm, but I'm skeptical. I have a lot of friends who are or have been in this position, and they tell me that the "part time" gig is "part time" mostly in name. Yes, you're not on the hook every hour of every day. But you're working a full-time job by most measures; working "part time" at a large law firm might mean only 40-45 hours a week. Or so I hear, anyway. As for making partner, I'd be interested in the numbers, both in terms of part-timers making non-equity partner and becoming equity partners.
To be clear, I don't mean this as criticism of law firms, especially the "biglaw" firms that often have these sorts of policies. Large law firms are businesses designed to maximize profits. When you charge by the hour, you maximize profits by maximizing the number of billed hours and minimizing overhead by limiting the number of workers who must receive offices and staff support. The firm with lawyers that bill the most hours will tend to be the firm that makes the most money, and if you want to make big firm money, that's the world you've chosen. But based on what my friends at big firms tell me, I'm skeptical that these part-time gigs are actually as part-time as the firms suggest.