As far as where I'm coming from, I grew up in West Virginia, which was not exactly a wellspring of egalitarian thought at the time, and where my parents were casually prejudiced about all kinds of things. I try very hard not to be. It's a matter of accepting you have patterns of thought, and actively working to be sure that you didn't just talk from there without considering whether you've said something you didn't actually want to say to a casual stranger or a friend.
And I'm sorry to have hijacked the thread so badly, but I was really shocked to see that DrHyde had gotten downvotes for pointing out that "some girl" wasn't a good way to put it. Perhaps his not saying why he didn't like it would have been more useful - but downvoting says "this was an incorrect and inappropriate thing to say", which definitely is not the case.
"Some girl" says "please apply whatever set of default assumptions you have about women to this person". "Someone" says "just a person, and what race, color, or religion they happen to be is completely irrelevant". If it was a dear female friend, then to me it feels appropriate to say that specifically. Even "my lovely girlfriend" wouldn't have caught my attention, let alone bothered me. But "some girl" really grates on my nerves, sort of like "they're all interchangeable anyway" - which I am totally sure you did not mean...but it isn't about what you mean, but what you say.
Let me make it clear that I am not trying to bust your chops - I am trying to communicate something I've learned about how this can come across to someone who you actually like and had no intention of offending or saddening. I would like the Perl community to be one that women and minorities feel comfortable in, and showing that you actually think about that helps a lot.