Since the beginning of the coronavirus pandemic, the prevailing wisdom from government officials and much of the scientific community is that the SARS-CoV-2 virus originated in an animal and at some point jumped to humans. The idea that it might have accidentally escaped from a lab has been widely dismissed as conspiracy theory, partly because it was easily conflated with inflammatory rhetoric coming out of the Trump administration. But plenty of scientists and policy have quietly taken the so-called "lab-leak hypothesis" seriously and now that the volume has been lowered on some of Trump's more dangerous distortions they're starting to talk about it.    Two experts that have been talking about it all along are Dr. Alina Chan, a molecular biologist at the Broad Institute of MIT & Harvard, and Dr. Filippa Lentzos, a biosecurity expert and senior research fellow at King's College London. Together, they spoke with Meghan about what we do and don't know about the origins of the virus, why knowing the origins matters in the first place, and, above all, why people have such difficulty separating the idea of a deliberately released bioweapon, which no serious person has suggested, with the possibility of an unintentional lab spill-over, for which there is plenty of room for questions in this case.   Guest Bios:   Dr. Alina Chan is a recent Human Frontier Science Program fellow with 12+ years of research training in medical genetics, biochemistry, synthetic biology, and vector engineering. At the Broad Institute of MIT & Harvard, Dr. Chan is currently researching next generation AAV vectors for human gene therapy. During the COVID-19 pandemic, Dr. Chan began to investigate problems relevant to finding the origins of the SARS-CoV-2 virus and spearheaded the development of the COVID-19 CoV Genetics (covidcg.org) browser for scientists worldwide to rapidly track emerging SARS-CoV-2 variants by locations and date ranges of interest. Follow her on Twitter @ayjchan.   Filippa Lentzos, PhD, is a Senior Research Fellow at King's College London, where she has a joint appointment in the Department of War Studies and the Department of Global Health & Social Medicine. She is also an Associate Senior Researcher within armament and disarmament program at the Stockholm International Peace Research Institute, a biosecurity columnist at the Bulletin of the Atomic Scientists, an editor of the social science journal BioSocieties, and the NGO Coordinator for the Biological and Toxin Weapons Convention. Her May 5, 2020 article on the need for a credible investigation into the virus's origins appeared in the Bulletin of the Atomic Scientists. For more about her work see www.filippalentzos.com or follow her on twitter @FilippaLentzos.