I’ve been learning about taharat hamishpacha and my lessons say that when a woman finds a spot of questionable color while counting the 7 clean days, she must take it to a rabbi for him to look at it. That seems incredibly uncomfortable, and even immodest. How could it be that a man cannot see my upper arm, but he is expected to see my bodily fluids – something I’d even be embarrassed to show to my husband?
Also, what gives the rabbi the ability to make the call whether a spot is liable to make a woman considered still in niddah or not? Is it simply traditional methods passed down, is there medical speculation involved, and could different rabbis potentially say different judgements about the same spot?
Can an experienced, halachically informed woman not do so for herself?
On a side note, I was wondering about the white underwear. If spotting occurs on white underwear, it almost invariably stains. This means that each pair of underwear is unlikely to be purely white foe more than one cycle. Are we just supposed to go through underwear and keep buying new ones? If not and it’s okay to re-use the stained underwear, then why is any off-white color garment unacceptable when it is essentially the same if the white garment is no longer white?