Different buttons for boy's shirt from a girl's shirt

If you mean why they are sewn on different sides of the shirt, I heard one unverified story that it is tradition. Back in earlier centuries men usually dressed themselves but women needed help, and so they put the buttons on the other side so that the ones helping the women to dress could more easily fit them through the button holes. If you meant something else, sorry ....

So you can tell the difference? just guessing, I really have no idea.