The developmental process of myelination and the adult regenerative process of remyelination share the common objective of investing nerve axons with myelin sheaths. A central question in myelin biology is the extent to which the mechanisms of these two processes are conserved, a concept encapsulated in the recapitulation hypothesis of remyelination. This question also has relevance for translating myelin biology into a better understanding of and eventual treatments for human myelin disorders. Here we review the current evidence for the recapitulation hypothesis and discuss recent findings in the development and regeneration of myelin in the context of human neurological disease.