3.You can have two of them (sorta).
Embryologically, the vagina forms from two tubular structures that fuse in the middle. The divider along the midline disappears during development. But occasionally it doesn't, so some women are born with a septum that divides the vagina into two. While some opt to have it removed, others may not even know it's there. It'll just push to one side or the other when inserting something, like a tampon, a penis or a dildo.
