Pregnancy is often perceived as a simple nurturing process, but it's actually a complex struggle. The placenta, a temporary organ, is crucial for human survival and plays a key role in this process. Radiolab explores the placenta's 270-day life, revealing its multifaceted nature beyond just an organ. It acts as both a foreign invader and a vital partner for the developing fetus. The placenta is described as a piece of meat, a friend, and a parent, highlighting its diverse roles. This episode, originally released in 2021, delves into its essential function in the survival of our species. Numerous experts contributed to the reporting and production of this episode. The episode cites research papers by Harvey, Julia Katz, and Sam Behjati. Radiolab encourages listeners to sign up for their newsletter and support the show. Funding for Radiolab's science programming comes from various foundations.