Do you know the sex of your cells? Not a question that is frequently heard around the lab bench, yet thanks to recent research is probably one that should be asked. It is self-evident that cervical epithelial cells would be derived from female tissue and prostate cells from a male subject (exemplified by HeLa and LnCaP respectively), yet beyond these obvious examples, it would be true to say that the gender of cell lines derived from non-reproductive tissue, such as lung, intestine, kidney, for example, is given minimal if any thought. After all, what possible impact could the presence of a Y chromosome have on the biochemistry and cell biology of tissues such as the exocrine pancreatic acini? Intriguingly, recent evidence has suggested that far from being irrelevant, genes expressed on the sex chromosomes can have a marked impact on the biology of such diverse tissues as neurons and renal cells. It is also policy of the American Journal of Physiology, that the "........source of all cells utilized (species, sex etc) should be clearly indicated" when submitting an article for publication, an instruction that is rarely followed. In this review we discuss recent data arguing that the gender of cells being used in experiments can impact the cell's biology, and provide a table outlining the gender of cell lines that have appeared in AJP Cell over the last decade.