They didn't choose their sexuality when they were born, so I guess it is unfair to judge someone based on their sexuality. Perhaps a long time ago when woman had not had their credibility like they have nowadays, no one would feel comfortable being taught by a woman. However over the time, people start to loosen up their fanatical belief, and became more open minded.
Why this thing can't happen again to Gay, if straight man who molested, abused children can be accepted as a bishop (no offense here just giving an example in real life), why a gay who actually never harass their student, give good example, and passionate in teaching the good nature of life can't be a bishop.
In the end, what is written down in the bible was interpreted by so many people in the past, and we can't deny they were all human not an angel or god/es. Surely, their interpretation would be based on morale value during their living time which is way in the past. So, the authenticity of what is written down should be in question. (again no offense)