And this is where I lose half my readership. I was going to save this post for later, after I explored niddah a bit more, but a conversation in the comments section here has prompted me to post it now.
I would love to be a fly on the wall on the day at Rabbi School, when the future rabbis are instructed on how to analyze vaginal discharge stains on underwear. What possible knowledge is imparted during this class that a woman could not decipher herself? If the analysis is based on dimension, couldn't she use a transparent ruler with cutouts that indicate niddah in size? If it is based on colour, can't women use a paint chip that would let them evaluate the colour? We choose wall paint this way all the time! How different could it be? And although empowering women may not be a top priority in UO circles, surely "modesty" is. It is mind boggling to me that in a culture where showing ones knees/elbows is considered immodest, showing ones dirty underwear to a rabbi is OK.
I feel dirtier just having written that post. But it had to be said.