I never thought of this really. But I do tend naturally to sit cross legged. But I guess it's a physical thing as I have long slim legs, much to my wife's chagrin as hers are less so.
I hardly ever sit legs apart it feels wrong possibly because I grew up in a house full of girls.
But there is a good reason for men to do so. Testicles need to be lower than body temperature to maintain fertility.
