There exists an obvious but thin reason to segregate men and women in select sports – and that is testosterone. All arguments of female body builders aside, in only highly physical sports, such as American football, basketball, hockey, men at a peak physical condition will perform better than female counterparts. This accounts for the existence of a separate basketball league in the States (WNBA), for instance, since otherwise most women with maybe the rare exception would not be able to enjoy opportunities to play basketball professionally. However, such reasons to segregate competitions by gender don't make themselves so immediately obvious when it comes to gaming.
However, in many sports, gender segregation has very little justification save for following the status quo that has been in place for well over a century. The first I've observed tackle this head on is auto racing, and I don't think it's really as much NASCAR encouraging the idea rather than headstrong female drivers proving themselves on the track to the dismay of grey-haired pit managers who would vote Pat Buchanan into the White House.
I digress; my point is that these plucky racing pioneers have made a realization that the people behind the ESWC and CGS would be smart to make – that in most sports and competitive games, gender doesn't mean shit.
Holding a separate competition for men and women in key pushing and mouse movement with a second course of strategic and tactical planning and teamwork with finely tuned hand-eye coordination for desert – otherwise known as Counterstrike – as the ESWC has done, is simply useless and counterproductive. Similarly backwards is having separate competitions for male and female Dead or Alive players, as is being done in the CGS.
Whatever marketing arguments that might be made regarding a gender division to 'highlight' female gamers and attract a less male-heavy audience, while its intention is good, are quite possibly achieving the opposite. Gaming events being done with such a high profile would do so much to attempt attracting the female demographic into such a male dominated activity by using their event as a platform to further gender equality by not segregating genders in their competitions. It's not even enough to merely pit the sexes against each other, it's about realizing that competitors in gaming competitions can be gamers first and be of a gender second, that your hormone production has no impact on your ability to play video games.
At the least, such practices can certainly be chalked up as a missed opportunity for gaming to make a real impact on today's mainstream dynamic.