Do online games like World of Warcraft lead to bad parenting?

I'm sure there are a lot of parents who game and will take offence to this questions, but this is a problem within my extended family and wanted to see other thoughts.

I have a relative who has been a parent for 12 years now and about 3 years ago he got involved with World of Warcraft. Prior to that he was always an involved parent and he was always at family gatherings or doing things with his children. This past year has been the worst so far. His marriage is on the verge of collapse and most of us hardly ever see him. The last family gathering led to his wife breaking down before a few of us as she told us how he doesn't pay attention to them when he is playing.

I realize this is most likely a character flaw rather than the game being to blame. But prior to this, he really was a good father and husband.

Thoughts?