Human Spermatogonial Stem Cells Scrutinized under the Single-Cell Magnifying Glass

Spermatogonial stem cells (SSCs) are essential for adult spermatogenesis. Recently, Wang et al. (2018), Guo et al. (2018), and Hermann et al. (2018) used single-cell RNA sequencing to define and molecularly characterize human testicular cell populations, including spermatogonial subsets with characteristics of human SSCs.