I used to play Guild Wars and then Guild Wars 2. When I started my guild, everyone just assumed I was female. As a result we attracted a lot of women and families. A lot of my members grew with the guild from childhood into adulthood because their parents were also playing.
But I would say that about 40-50% of the guild was female. Later when we formed alliances, I would put it as about 25% of the alliance was female. A guild = 100 people at full capacity and we had a policy that you had to be active. An alliance was 10 guilds.
Guild Wars 2 the dynamics changed slightly because my guild was also split 50/50 between the US and Europe. GW2 meant that it was difficult to stay together as a guild, especially as many of us had drifted into pvp. I was on SFR server when it started to rise and eventually dominate pvp. I would say that there was a healthy number of women on the server. The guild that I joined was male led but had a lot of female members... not as many as the guild I started myself but still about 20-30% female. However, I only ever heard one female commander on the server. The commanders were almost all male but we did have an openly gay commander for a while.
...And the women were just as good and often better at playing than the men.
Also, many women, in fact most of them, played male characters. It caused a lot of confusion when people heard my voice for the first time. Because people thought that the voice from the woman playing 'bob' was me, and that my voice was 'bob'. When it finally twigged that the voices and characters were not matching it caused a big stir in the guild. Several members left. I got a lot of abuse from some about being gay etc. As it turned out, quite a few of members in the guild had a crush on me. But we overcame that, it was sad that people no longer treated me as female, the language became a lot worse, so I had to introduce a rule of 'no swearing' because we were still a family guild. People were less kind, less helpful, and more aggressive... so in the end I stepped down as leader and put a cis woman in charge of the guild so that it returned to a better atmosphere again.
She had 90% control to do her own thing but any major changes had to be passed by me. Namely the only main thing was that the cape and logo stayed the same. I spent a lot of time and effort in the guild branding which is part of the reason why we became an Anet notable guild and were invited to alpha test GW2.
But, yep, definitely has been an increase in female gamers.