The Gemara (Megillah 23a) states that a woman may not be called to the Torah because of kevod ha-tzibbur. R. Yosef Qafih* (commentary to Mishneh Torah, Hilkhos Tefillah ch. 12 n. 49) offers an interesting explanation - that I have not seen previously cited - of the enigmatic phrase "kevod ha-tzibbur." He suggests that since Torah reading requires a minyan of ten men, it is disrespectful to those who are needed for this minyan to call to the Torah someone who is not needed.
* Note that spellings of his name in English vary widely. I am using the spelling on the English title page of his collected writings.