Well, I'm a female-bodied and a gamer, but not exactly a girl. I love pen and paper RPGs and video games. I first started on Vampire: the Masquerade (ha ha I know, I actually still play it) when I was 13, and I've been rolling dice ever since.
As a transgender guy who right now presents as a girl, one of my favorite things about my (otherwise all biomale) gaming group is that they treat me like one of the guys. I don't think they'll be that surprised when I come out to them. They occasionally make fun of me for being masculine as a female, but that makes me feel good because they also accept and even like that about me. Another great thing about them is that it's very common for group members to play characters of the opposite gender-- something which more 'conservative' (i.e. NO GIRLS ALLOWED) gaming groups apparently don't allow. I usually play male characters, but also play females occasionally.
There's still a lot of sexism in the gaming community (you wouldn't believe how many guys I've talked to who put women on a pedestal and simultaneously bash 'slutty girls'), but I hope that as gaming becomes more accessible to girls over the years, more girls will get involved and break down assumptions.
Honestly, while roleplaying can be a great way to have silly and/or dramatic fun, I think that it's a real relief for some transpeople to be able to play their real gender with no discrimination. At least for me it is-- since I never pass as male, it's an opportunity to be seen and treated as male, even if it's only in a fictional setting.
