Hello. I teach band at a public high school in North Central Iowa.
Licenses are earned through certain requirements from coursework and/or teaching experience. Most states, including Iowa, have some sort of requirement of taking a course based on the history of education in that particular state. If a teacher were to come in from out of state, they would have to take a course, or potentially multiple courses depending on the licensure requirements of the state they come from. That being said, the BoEE offers programs to teachers moving in from out of state; most can apply and use a temporary license for a few years while finishing any other requirements for Iowa's license. This can almost always be easily done during summers and nights if the candidate already has a teaching license in another state.
Personally, I technically have two endorsements; Music K-7, and Music 5-12. Almost every high school band director/choir director I know has those same endorsements. The requirements to earn these endorsements are in the classroom, taking a cumulative exam (Praxis), and a certain amount of experience in the classroom, which is met for most teachers during their collegiate career with student teaching/practicum, or upon renewal from their actual teaching experience.
Most endorsements have a breakpoint depending on grade level; as I said before, music splits into two categories, K-7 and 5-12. These are not meant to be punitive or gatekeeping in any way; teaching elementary music is vastly different from teaching an instrumental ensemble in the upper grades.
Working with students at different grade levels can have incredibly different experiences. While it's often easy to make fun of all the red tape, teaching special ed at the HS level is nothing like teaching general mathematics in third grade, other than the low pay. In order to get your educational license, you must take certain coursework, regardless of endorsement. You must pass a background check, and you must pass a general test covering (mostly) developmental psych, and educational theory/foundations. You then get endorsements in whichever content areas you wish to teach.
Perhaps as a licensed teacher this makes me biased, but in teaching, you must have mastery of your material and subject. Your job is to teach and pass on that information to the students in an interesting, engaging, memorable way, whilst simultaneously teaching them the soft skills necessary to succeed after secondary school. I do not see an issue at all in requiring certain licensure in order to teach certain courses. Frankly, I find many of the responses here indicative of the public sentiment towards teachers; "anyone could do it! Why are we paying for babysitters?!"
That being said, there are avenues and opportunities to earn a teaching license without having the specific education degree; I do not know the ins-and-outs of these, as I am a more traditional teacher, but I am aware that Iowa allows professionals who have the want and passion to work with young people the opportunity to do so. I would suggest contacting the Iowa BoEE with further inquiries.
