Unlike most girls, I am perfectly content with going to the bathroom by myself.  Why drag someone away from what they're occupied with, just so I can go pee?  It never made sense to me, but after thinking about it, I can offer some insight into the question.  So, all you curious guys out there- listen up!

     It's really, really simple.  It's a matter of confidence.  At least, it is in most cases.  Let me explain.

     At restaurants, movie theaters, and even study hall, I generally get asked to accompany a friend to the Ladies Room.  To which, I swiftly reply with a simple, "No."  Then comes the looks that reads, "Oh my god, why not?" all over her face.  Sometimes my reply is returned with a scoff, other times the question is verbalized.  We're not four years old anymore.  Nobody needs to hold your hand, nothing is going to happen to you between here and the restroom.  A girl who is confident will just excuse herself from the table, letting others know she's headed to the Little Girls' Room, (when someone may jump up and decide to accompany them, just for convenience's sake).  No need for a bodyguard, or someone to chit chat to over the top of the stall.  However, a girl less secure will find she needs someone to cling to in her voyage to the bathroom, perhaps too afraid of being assaulted along the way.  Most girls are less secure than they appear.

     The only situations I personally could justify this behavior for my own gender is in large, social gatherings, like a school dance, at a club, or a huge party.  Girls tend to come with one or more friends, and make sure to leave with those same friends, and making a group bathroom trip will make the chances of that happening even greater.  Who likes being alone in a large group of strange people?

     It might not be a definite answer, but hey, it's some insight, right?