|Shirt buttons are on the right side for men and on the left side for women. It is as simple as that.
My searching found several theories that exist to explain why.
--- Women breast feed
--- In Medieval times, women had handmaids to help dress them. Therefore the garments were designed so the buttons were in the proper position for the dressers, the person USING the buttons.
--- The right side because women's are on the left and women used to button men's shirts for them.
--- In France Napoleon ordered that all women's shirts be buttoned on the opposite side because women used to stick their hands in their shirts to mock him. With the buttons on the opposite side, women could no longer mock him.