Wang et al. developed a microfluidic method for single-cell, whole-genome amplification. This enabled the generation of detailed maps of recombination and mutation in sperm, thus revealing the changes that occur in individual meioses. The recombination rate was consistent with estimates from human population studies, although the sites of recombination hotspots differed. Furthermore, the authors quantified the rates of aneuploidy and de novo point mutations; such measurements of genomic instability are confounded by negative selection in population studies.