Bible science, hard to choose the looniest theory but this has to be mentioned. Have a woman sit on a wine cask, if you can't smell wine on her breath, it's because her intact hymen is blocking the fumes and therefore she is a virgin.
Of course this is ridiculous. The hymen has a hole to allow for menstruation so it is not a solid block. It would appear that the anus has a more direct route through the alimentary canal to the mouth. But this is a long 40 foot distance to travel through the body. Of course if one breathes in the wine fumes the woman would more likely have wine on her breath. The only thing proven by this experiment is that Christians lack scientific smarts.