AI has no gender, so why does it sound like it does?

Technology promises a future that isn't tied down by the limitations of flesh. Communication travels further and faster than legs can run, and data beamed into space will live longer than any of its creators. Devices that respond to our voices make hands less necessary. But the digital assistants many of us rely on inadvertently perpetuate the old restrictions of the human form. If Siri has no body, why does she sound like a woman?