Thousands of papers are submitted every month to the platforms arXiv and bioRxiv,which make manuscripts available before they have been peer reviewed and accepted by a journal.Scientists applaud preprints because they enable researchers to claim priority and make their findings available more quickly,unshackled from sluggish and tyrannical journals.This might make sense within the scientific community,but this method of publication holds substantial risks for the broadcr community-risks that are not being given proper consideration by the champions of preprint.Weak work that hasn"t been reviewed could get overblown in the media.Conversely,better work could be ignored.Many people still learn about science the same way they learn about Syria or the World Cup:through news sites,television and radio.The bulk of research reported through these channels is peer reviewed.A few days before a paper is published,the science journal will issue a restricted press release to qualified journalists under an agreement that no one will report on the paper until a designated time.The system has its flaws,but it does give reporters time to assess the research and gather expert reaction.Contrast this with preprints.As soon as research is in the public domain,there is nothing to stop a journalist writing about it,and rushing to be the first to do so.Imagine early findings that seem to show that climate change is natural or that a common vaccine is unsafe.Preprints on subjects such as those could,if they become a story that goes viral,end up misleading millions,whether or not that was the intention of the authors.Another risk is the inverse-and this one could matter more to some researchers.Under the preprint system,one daring journalist searching through the servers can break a story;by the time other reporters have noticed,it"s old news,and they can"t persuade their editors to publish.There have been cases in which a preprint that garnered news stories got a second wave of coverage when it was published in a journal.But generally,the rule is"it has to be new to be news".It is not enough to shrug and blame journalists,and it is unhelpful to dismiss those journalists who can accurately convey complex science to a mass audience.Journalists do include appropriate warnings or even decide not to run a story when conclusions are uncertain,but that happens only because they have been given enough time and breathing space to assess it.If the scientific community isn"t careful,preprints coulcl take that resource away.How can we have preprints and support good journalism?Should scientific societies or preprint advocates develop guidelines for what should and should not be posted as a preprint?Should all preprints be emblazoned with a warning aimed at journalists that work has not been peer reviewed"?Preprints could bring great prizes for science.But these questions must be brought up now,so that public understanding is not damaged as preprints flourish. Traditional research reporting channels