What's the deal with blood types?

4/9/2015, 3:14:45 PM , duration(0:0:3)
Society & Culture
Blood types have one of the more interesting backstories in medical history. But as much as we've figured out about them and how they work, we still don't know much about why we even have different blood types. Listen in for a truly fascinating look at your most essential bodily fluid.<br><br>Learn more about advertising on the HowStuffWorks podcasts at <a href='http://www.howstuffworks.com/advertisers.htm'>www.howstuffworks.com/advertisers.htm</a><br><br>And to learn about your ad choices when listening to podcasts, visit <a href='https://www.howstuffworks.com/privacy.htm#ad-choices'>https://www.howstuffworks.com/privacy.htm#ad-choices</a>