wmscott writes:
Since it is possible to change, it is a matter of choice.
I was born bipedal. Nowadays, I'm not so sure whether I still like being bipedal that much anymore. Hopping around on one leg has its appeal after all, right?
Luckily, medical science has advanced to such a degree that I can now, at last, have one leg surgically removed. (I'm still wavering, so to speak, about which leg I am going to part with, though.)
I am greatly strengthened in my resolve by wmscott's assurance that, since it is possible to change, being bipedal is a matter of choice, as is becoming monopedal.