We have long known men's shirts have their buttons on the right - while women's blouses button on the left.
But it's safe to say no one has given much thought to why - until now.
A debate has broken out over the reason for the difference, after someone posted the seemingly straightforward question on an internet forum.
Writing on the website Quora, which allows users to post questions for those with expertise on the matter to answer, commenters came up with countless theories ranging from the archaic to the ridiculous. One user, Will Wister, claimed the side on which buttons are sewn is historically related to how the different genders got dressed.
He said: "Women were dressed by servants who tended to be right-handed, while men tended to dress themselves."