I wonder if there are studies showing that boys are more likely to have dyslexia, etc. as lefties. The boy in my first grader's class who has serious ADHD, etc. is a leftie. His writing is very dysgraphic.
My mother was a leftie who got switched as she entered first grade. She stammered as a child, but that went away.
My grandma was a total leftie. They tried to switch her and it didn't work. She had lots of problems using scissors, eating in a restaurant as a leftie, etc. so I've always had the impression that life is so much harder as a leftie!
Although in today's world, it's easy to get left-handed scissors. I do think if your son is a baseball pitcher, it's better to be a leftie!