Very nicely said GamerDad - to me the issue isn't that he's playing so many games, but rather *why* he is doing it, and *how* he is going about ensuring it as a 'natural right', and the fact that he has created a void between you and his mom over this. That last one screams 'power struggle' and your posts indicate that he has 'won'. Not saying it is good or bad, just like GamerDad says, struggle at that age is essential and particularly with 'mixed marriage' families where there is an added element of powerlessness for kids. My point is that you and his mom need to come to an understanding over this - even if it is just a matter of saying 'we fundamentally disagree, but you are his mom and while I see some serious potential issues I will respect your decision'. The problem there is the backlash - if she has said she gives you no authority to regulate how he spends 25% of his life, she then has no right to expect you to attempt to regulate how he spends 25% of his life. Not an easy situation ... my big concern is that if it is happening over video games today, what will it happen with tomorrow?
Growing up my parents were concerned at anything that overly occupied my time - whether it was music, sports, reading, writing, arcade time, part-time job, school work or whatever. Their watch word was 'balance' - they knew I was destined for technology of some type, but because of their push for balance I was guided by my music & band teacher to interview at the Berkeley School of Music and by my literature teacher to submit a short-story and poem to the Atlantic Journal and to consider going into writing. (they told me later they were glad I opted for a path with 'earnings potential'

)
I just look at it this way in terms of time:
- 168 hours a week
- 8 x 5 = 40 hours of school
- ~10-15 hours of homework
- 56 healthy sleep hours (which some would argue should be 70 for a teen)
- That leaves 50 - 60 total hours remaining, including 32 for weekends. Taking away 40 hours leaves about 2 hours per day to eat, shower, talk to actual people, and do other things.
To me that would cause a concern as a parent. Again, not because it is computer games but because it is a single activity, and despite virtual socialization it is still largely a singular activity. That doesn't make it evil, bad or wrong - simply an area of concern.