Currently there are two basic approaches in the United States about how to teach singing to boys whose voices are changing. One is the method used by many boychoir directors who keep the youngsters singing in the head voice (may be called "falsetto" after the voice has begun to lower) throughout the change and even encouraging some of them to continue to sing male alto (countertenor) as they become older adolescents and adults. This approach works well in a closed community of boys outside the influence of other boys who do not sing. They support each other in the music making process when they are in an environment where they all may engage in this common practice.
The other approach is taken by most (not all) church musicians and music educators where there is not a close knit community of male singers to support each other. In churches and schools boys may come to the choral situation with little or no knowledge about how to use the head voice. Some may not have attempted to sing at all until the mid-level grades (they may have chosen to sing in choir simply at a friend's encouragement). Usually these boys relate singing in head voice to the way females sound, so they view head phonation as an infringement upon their masculinity. Due to a macho mentality displayed in the family (usually encouraged by a dominant male figure) or because of the influence of male teachers and other boys, they think it is not masculine to sing in head voice. Therefore, many teachers feel it is important to encourage the use of the boy's emerging "male" octave (called "chest" or "modal" phonation). The difficulty with this approach is that the further they progress through the change, the more difficult it becomes for them to move through the passaggio (the "break" or "passage") which separates head and modal phonation. The passaggio becomes so wide (with some boys) that they can't produce any tones at all around middle C (the proximity of the passaggio during the second phase of change).
To alleviate this problem, many teachers choose music that attempts to keep the young male singing in the most comfortable portion of modal phonation (sometimes less than an octave) so the boys do not have to move through the passaggio. As the boys' voices continue to change, the passaggio gradually lowers, as do the tones in modal phonation. Directors constantly must be aware of where these comfortable tones lie, so they may place the boys on the most singable part in the literature. The more options (available parts) teachers have from which to choose, the more likely the boys will be comfortable and productive in the singing process. Many schools have uni-sex classes for boys and girls in the mid-level grades. Putting three grades of boys together (usually 6th, 7th, & 8th) affords three or four parts (CCB, CBB or CCBB) from which teachers may choose when searching for a part in the music with a comfortable singing area for various boys to sing. If school or church protocol calls for uni-grade classes, directors may choose to teach the grades separately then combine them for concert or worship services. In four-part mixed music (boys and girls singing SSCB voicing together), there are at least two boys' parts from which to choose, an option significantly better than having only one part that all boys must sing (SABoys).