David Bennett has become the first person in history to have a pig to human heart transplant. Scientists have edited several genes to make this possible. On the pod, the team say that if it proves successful longer term, it could be a game-changer for medicine. In cetacean news, have you ever wondered why dolphins have so much sex? Patricia Brennan from Mount Holyoke College in Massachusetts has been studying dolphin clitorises, and shares her findings with the team. We now know much more about the omicron variant of coronavirus, and with more than half of people in Europe set to catch it in the next 6 to 8 weeks, the team explains why the variant is more infectious. There’s a double dose of moon news this week - first there’s the discovery that Saturn’s moon Mimas may have an ocean beneath its surface, and then we have the first water ever detected by a robot on our Moon. And novelist and New Scientist columnist Annalee Newitz joins the discussion to share their experiences with a robot therapist called Woebot. On the pod are Rowan Hooper, Penny Sarchet, Clare Wilson and Leah Crane. To read about these stories and much more, subscribe at newscientist.com/podcasts. Thanks to our sponsor Brilliant - remember the first 200 people to sign up using this link http://brilliant.org/newscientist will get 20% off unlimited access to all the courses on Brilliant for a whole year. See acast.com/privacy for privacy and opt-out information.