I find this topic fascinating!
I'm confused by the posts above, though. If you start a cartwheel or roundoff with your left foot, does that make you left footed or right footed? (Someone above seemed to indicate that it makes you right footed - meaning that is your stronger foot/leg?)
I am a righty but am a lefty for gymnastics - left leg split is much better, do cartwheels, roundoffs, etc with left foot down first. I never got to twisting in gymnastics but am sure I would twist left. I cannot even turn to the right as it feels extremely unnatural for me. I kick a soccer ball with my right foot though, can balance on my left foot extremely well but very poorly on my right foot alone, and skateboard, snowboard, and scooter with my left leg in front. I also used to swim competitively and started off the blocks with my left leg in front.
I always figured that my right foot/leg was stronger, and given I am right handed, I thought that made sense. But when I was a kid doing gymnastics, I was in the huge minority, starting with my left foot.
My dd also writes with her right hand and is a lefty gymnast. But she rides a scooter with her right leg in front and pushes off with her left leg, and can't do it the other way. She can do a righty cartwheel and roundoff much better than I could ever have from my "bad" side, though, although it's not as good as her left side. Her team has slightly more righty gymnasts than lefty, but they seem fairly close to equal (maybe 60/40) whereas I distinctly remember that I was usually the only or one of 2 kids in my group who were lefty gymnasts.