Expecting: Pregnancy souvenirs

Fetuses leave cells behind in their parents' bodies, where they braid themselves into tissues, and remain, for years. What are they doing in there? For more, go to http://vox.com/unexplainable It’s a great place to view show transcripts and read more about the topics on our show. Also, email us! [email protected] We read every email. Support Unexplainable by making a financial contribution to Vox! bit.ly/givepodcasts Learn more about your ad choices. Visit podcastchoices.com/adchoices