I guess it depends on the issue, but up to now I have been able to talk both to girls and boys about similar problems, and both had valuable inputs. I'm a male btw.
I mostly assume that I am talking to a male actually when I connect as a venter, and sometimes I don't know my listener's gender until an hour in the conversation (yeah I talk a lot).
Don't worry about it, people who think boys are not good listeners, or venters who are actually looking for a chat with a girl, are just a minority.
Keep doing what you do, it's very generous of you to take time to listen to people struggling, consider that people who turn away from you are simply missing out on valuable advice.