In my opinion, countertenors are great. These are men who can sing a high tenor voice through the use of falsetto or sometimes natural head tone. If there is no available female, the countertenor can replace the part of the alto, mezzo or soprano range. Also, a trained countertenor is more similar to a mezzo-soprano. I experienced listening to a countertenor recording and it amazes me. Just close your eyes and you will forget that a real guy is singing.