Prof Dr Frank J.T. Staal obtained his bachelor and master degrees (both cum laude) in Medical Biology at Utrecht University. He obtained his PhD degree (1993) at the Department of Genetics, Stanford University School of Medicine under the supportive guidance of professors Leonard and Leonore Herzenberg where was taught the intricacies of flow cytometry. His thesis dealt with transcriptional regulation of HIV expression in T-lymphocytes and involved many functional flow cytometric assays and cell sorting experiments. In 1993 he became postdoctoral fellow at the Netherlands Cancer Institute for 2 years, after which he moved back to Utrecht University as fellow of the Royal Academy of Sciences (KNAW) in the laboratory of professor Hans Clevers. In 2000 he was recruited to Erasmus Medical Center (EMC) Rotterdam to start his own laboratory on human T cell development and became assistant professor. In 2004 he was appointed associate professor at EMC and expanded his research to Wnt signalling in blood stem cells and T cells, as well as to gene therapy for immune disorders. In 2008 he was recruited to the Leiden University Medical Center (LUMC) and became full professor of Molecular Stem Cell biology. His current efforts are largely directed at getting stem cell based gene therapy for RAG1 and RAG2 deficient SCID into clinical implementation. He also works on epigenetics and transcriptional regulation of lymphocyte development, development of human thymus organoids and stem cell based gene therapy for various genetic diseases.