I love statements that are based on dubious studies of which noone can really say if they really took place, if they were representative, or flawed in design (the article doesn't even state what game(s) was used). And unless I've seen that study from Nottingham Trent University I'll just claim that this study is utterly rubbish. Simply because my experience tells me otherwise. I'm playing MMORPGs since the very beginnings of Everquest now and from my experience women less often switch gender in a MMO than men. Now, how can I know that? In all MMOs I've played over a long time I sooner or later ended up in a raiding guild and even at the good old Everquest times we used Teamspeak or similar technologies. With very few exceptions all the women in these guilds played female characters while quite a few male players created female avatars.
When it comes to the topic of sexual harassment the article certainly has a point. There seem to be quite a few male players around whose hormones are running wild as soon as they see a female character. But again I'd argue that depicting women as helpless victims is utter bull. Most MMOs have an ignore function nowadays and verbal harassment can easily lead to your account being closed. And, after all, female players can chose with whom they play and with whom not.
Another idiotic assumption is this one:
When it comes to multiplayer games, such as World of Warcraft, women must also face down a whole set of assumptions about their ability to play.
I can't of course say that it does not happen, but I've never seen it happening. In all my gaming time gender never played a role when it came to things like approving an application for a raid group or guild for example.
Character creation is also a thing which has to be seen in a rather objective and not feminist way. I would think that the majority of players, as Skavenhorde has already mentioned, does in fact want to play a hero that looks heroic and not like the village idiot (if you really want to look like one try LOTRO and play a halfling). I'd guess that this goes for men and women alike. Don't get me wrong, I'm not against giving players the possibility to make an ugly, fat and from a hygienic point questionable character, but for me it's perfectly understandable why the creators of MMOs stick to the "heroic appearance" pattern. Apart from that I'd really like to see the outcry from some feminists if a game would actually give you the possibility to change your (female) avatar's breast size...