Cytosine DNA methylation is an epigenetic mark associated with transcriptional repression, providing critical control over development as illustrated by the embryonic lethality of DNA methyltransferase (Dnmt) mutant mice. Twice during mammalian development, DNA methylation patterns are extensively reprogrammed. The first remodeling coincides with the transition from a somatic to a germline fate, while the second precedes the formation of the different somatic cell layers. What role DNA methylation plays in these early lineage decisions? I will present the latest work from our lab, which highlights that DNA methylation restrains the availability of enhancer sequences to allow differentiation paths both in the context of mammalian spermatogenesis and early embryonic development.