Puberty is definitely one of the major issues of middle school education.  Changes in the human body will override anything else that will go on in the classroom.  When a student has a puberty issue, learning is usually the last thing on their mind.  And nothing will make a class stop more than when a student has a accident.  Diversity in this issue is important to allow every student to go through these changes as semlessly as possible.  As important as puberal diversity is, I think it is a more cultural issue and I don't know the way this issue is dealt with is so diverse that it may upset the classroom learning experience.  Even if it is celebrated by their families, all it may mean is a day or two off of school.  We need to create a secure environment for all students, so they can handle these change or celebrate them in whatever way they wish.