Cell fate decisions are defined by the implementation of cell type-specific gene expression programs. Gene expression decisions are inherently binary–a cell either expresses a gene or it does not. It has recently become clear that the two copies of a gene in diploid cells do not always come to the same decision, despite sharing a trans regulatory environment. While this was thought to be restricted to small subsets of autosomal genes (albeit a surprisingly large proportion of genes!), my graduate work provided evidence that all developmentally regulated genes may be subject to stochastic allelic regulation, to varying extents. That is, rather than provide a certainty of a given cell type-specific gene being expressed biallelically, a particular trans nuclear environment raises the probability of gene allele expression.