This article explains the science behind Henry VIII's problem with siring male heirs. It is a good article not only for science classes (biology,health, etc) but for history classes too. If schools are trying to get a more cross-curricular approach to learning, then this article as well as the others in this series will help. Possible health issues discussed here for Henry VIII could have been the Kell blood type, McLeod Syndrome, and Syphilis. Red blood cell blood type antigens are briefly discussed.