You may have heard this maxim before. It is an attempt to relegate particular verbs into categories of social politeness. The raw, gross nature of sweat is too crude, even for a man. It comes from an earthy Germanic root, much unlike the scientific and placid perspire, a verb of Latin origins. Perspiration, unlike sweat, is devoid of its grosser implications. It contains a medical nuance and does not evoke the mental images of wet skin and soaked shirts. But women (ever the delicate creature, eh?) deserve a verb of noble sensibility: glow. The virtue of women is to be respected to the point that the only appropriate description of sweat on a lady is a euphemism.