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! unexplainable@vox.com We read every
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