Planet Money podcast

Listen this episode of the Planet Money podcast,https://www.npr.org/2020/07/15/891488686/summer-school-2-markets-pickles
Towards the end of the podcast they talk about situations where a market may or may not be the best solution. Professor Stevenson mentions organs as an example of where markets are not ideal, and Professor Wolfers disagrees. Who do you agree with? Explain and defend your answer.