It's kind of a mix for me, but I put down by choice. It's by choice for a couple reasons though, first and foremost being that I'm fifteen and dating seems a tad pointless right now for any reason but practice. Also, teenagers are generally irrational(save for the exceptions out there, bless your souls) and relationships kick up a lot of unnecessary "drama" that I don't wanna have at this age.
Second real reason being that, while I am unbiased friends with people of both genders, there are no girls I know that don't helplessly cling to their boyfriends and believe that you must be in constant contact every second of your life to make a relationship work. >.> Those are just the girls I know though. Yeah. No thanks.
Oh, and besides that, no girl I've ever really met has enough in common with me to sustain something like that. So yeah. There be my reasoning.