Today, a fast moving, sidestepping, gene-swapping free-for-all that would’ve made Darwin’s head spin.

David Quammen tells us about a shocking way that life can evolve - infective heredity. To figure it all out we go back to the earliest versions of life, and we revisit an earlier version of Radiolab. After reckoning with a scientific icon, we find ourselves in a tangle of genes that sheds new light on peppered moths, drug-resistant bugs, and a key moment in the evolution of life when mammals went a little viral.

Check out David Quammen's book The Tangled Tree: A Radical New History of Life 

This episode was produced by Soren Wheeler. 

Support Radiolab today at Radiolab.org/donate. 

More Perfect is back with something totally new and exciting. They just dropped an ALBUM. 27: The Most Perfect Album is like a Constitutional mix-tape, a Schoolhouse Rock for the 21st century. The album features original tracks by artists like Dolly Parton, Kash Doll, and Devendra Banhart: 27+ songs inspired by the 27 Amendments. Alongside the album they'll be releasing short stories deep-diving into each amendment's history and resonance. In this episode, we preview a few songs and dive into the poetic dream behind the First Amendment. The whole album, plus the first episode of More Perfect Season 3 is out now.

Support Radiolab today at Radiolab.org/donate. 

Horseshoe crabs are not much to look at.  But beneath their unassuming catcher’s-mitt shell, they harbor a half-billion-year-old secret: a superpower that helped them outlive the dinosaurs and survive all the Earth’s mass extinctions.  And what is that secret superpower? Their blood. Their baby blue blood.  And it’s so miraculous that for decades, it hasn’t just been saving their butts, it’s been saving ours too.

But that all might be about to change.  

Follow us as we follow these ancient critters - from a raunchy beach orgy to a marine blood drive to the most secluded waterslide - and learn a thing or two from them about how much we depend on nature and how much it depends on us.

BONUS: If you want to know more about how miraculous horseshoe crabs are, here's a bunch of our favorite reads:

Alexis Madrigal, "The Blood Harvest" in The Atlantic, and Sarah Zhang's recent follow up in The Atlantic, "The Last Days of the Blue Blood Harvest" 

Deborah Cramer, The Narrow Edge

Richard Fortey, Horseshoe Crabs and Velvet Worms

Ian Frazier, "Blue Bloods"  in The New Yorker 

Lulu Miller's short story, "Me and Jane"  in Catapult Magazine

Jerry Gault, "The Most Noble Fishing There Is"  in Charles River's Eureka Magazine

This episode was reported by Latif Nasser with help from Damiano Marchetti and was produced by Annie McEwen and Matt Kielty with help from Liza Yeager.

Special thanks to Arlene Shaner at the NY Academy of Medicine, Tim Wisniewski at the Alan Mason Cheney Medical Archives at Johns Hopkins University, and Jennifer Walton at the library of the Marine Biological Lab of the Woods Hole Oceanographic Institution.

Support Radiolab today at Radiolab.org/donate. 

Back in 2008 Facebook began writing a document. It was a constitution of sorts, laying out what could and what couldn’t be posted on the site. Back then, the rules were simple, outlawing nudity and gore. Today, they’re anything but. 

How do you define hate speech? Where’s the line between a joke and an attack? How much butt is too much butt? Facebook has answered these questions. And from these answers they’ve written a rulebook that all 2.2 billion of us are expected to follow. Today, we explore that rulebook. We dive into its details and untangle its logic. All the while wondering what does this mean for the future of free speech?

This episode was reported by Simon Adler with help from Tracie Hunte and was produced by Simon Adler with help from Bethel Habte.

Special thanks to Sarah Roberts, Jeffrey Rosen, Carolyn Glanville, Ruchika Budhraja, Brian Dogan, Ellen Silver, James Mitchell, Guy Rosen, and our voice actor Michael Churnus.

Support Radiolab today at Radiolab.org/donate. 

With all of the black-and-white moralizing in our world today, we decided to bring back an old show about the little bit of bad that's in all of us...and the little bit of really, really bad that's in some of us.  

Cruelty, violence, badness... in this episode we begin with a chilling statistic: 91% of men, and 84% of women, have fantasized about killing someone. We take a look at one particular fantasy lurking behind these numbers, and wonder what this shadow world might tell us about ourselves and our neighbors. Then, we reconsider what Stanley Milgram's famous experiment really revealed about human nature (it's both better and worse than we thought). Next, we meet a man who scrambles our notions of good and evil: chemist Fritz Haber, who won a Nobel Prize in 1918...around the same time officials in the US were calling him a war criminal. And we end with the story of a man who chased one of the most prolific serial killers in US history, then got a chance to ask him the question that had haunted him for years: why?

This episode was produced with help from Carter Hodge.

Support Radiolab today at Radiolab.org/donate. 

If there’s one thing Gonads taught us, it’s just how complicated human reproduction is. All the things we thought we knew about biology and sex determination are up for debate in a way that feels both daunting and full of potential. At the same time, we're at a moment where we’re wrestling with how to approach conversations around sex, consent, and boundaries, at a time that may be more divisive than ever. So host Molly Webster thought: what if we took on sex ed, and tried to tackle questions from listeners, youth, reddit (oh boy), and staff.

But instead of approaching these questions the way your high school health teacher might’ve (or government teacher, who knows), Molly invited a cast of storytellers, educators, artists, and comedians to grapple with sex ed in unexpected and thoughtful ways. To help us think about how we can change the conversation. In this episode, an edited down version of a Gonads Live show, Molly's team takes a crack at responding to the intimate questions you asked when you were younger but probably never got a straight answer to. Featuring:

How Do You Talk About Condoms Without Condom Demonstrations? Sanford Johnson. Wanna see how to put on a sock?

What Are Periods? Sindha Agha and Gul Agha. Check out Sindha's photography here.

Is Anything Off-Limits? Ericka Hart, Dahlia Mahgoub, and Jonathan Zimmerman 

Why Do We Do This Anyway? And Other Queries from Fifth Graders Jo Firestone

"Sex Ed" is an edited* recording of a live event hosted by Radiolab at the Skirball Center in New York City on May 16, 2018. Radiolab Team Gonads is Molly Webster, Pat Walters, and Rachael Cusick, with Jad Abumrad. Live music, including the sex ed questions, and the Gonads theme song, were written, performed, and produced by Majel Connery and Alex Overington. 

One more thing! 

Over the past few months, Radiolab has been collecting sex ed book suggestions from listeners and staff, about the books that helped them understand the birds and the bees.

Check out the full Gonads Presents: Sex Ed Bookshelf here! For now, a few of our favorites:

*Our live show featured the following additional questions and answerers:

How do you talk to your partner in bed without sound like an asshold or a slut? Upright Citizens Brigade, featuring Lou Gonzales, Molly Thomas, and Alexandra Dickson

What Happens to All the Condom Bananas? Rachael Cusick

With live event production help from Melissa LaCasse and Alicia Allen; engineering by Ed Haber and George Wellington; and balloons by Candy Brigham from Candy Twisted Balloons Special. Special thanks to Larry Siegel, Upright Citizens Brigade, and Emily Rothman and the Start Strong Initiative at the Boston Public Health Commission. 

Radiolab is supported in part by Science Sandbox, a Simons Foundation initiative dedicated to engaging everyone with the process of science. And the Alfred P. Sloan Foundation, enhancing public understanding of science and technology in the modern world. More information about Sloan at www.sloan.org.

Support Radiolab today at Radiolab.org/donate.