I'm a lefty as is my younger brother,our older sister is righty as were our parents. My brother's wife,also lefty,but their 4 kids aren't
I also experienced in high school not having a desk for lefty which felt strange.
I don't curl my hand either,but my writing does slant towards the left. In sports,playing softball I would bat&catch right handed,kick a football with my right foot,throw with my left hand. When I use to play tennis,I was taught how to slice the ball which gave my opponents fits,the extra ball always put in right pocket Sue