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Why So Many Sperm?

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Matthew Cobb takes us back to 1677, when Anton Van Leewenhoek first identified sperm and there was much talk of souls and miniature men residing in the seminal fluid. Upon observation it became clear that there were an awful lot of those little guys that never turned into babies! Jad wonders: why so many sperm? Bird-sex specialist Tim Birkhead, of the University of Sheffield, explains what effect imperfect monogamy has on reproductive strategies. Then sperm physiologist Joanna Ellington and her pig Hazel give us some insight into the obstacles sperm must overcome in their odyssey from their male originator to their female destination.

Comments [26]

Mark Werner from St Louis, MO

Back when I was a young lad interested in science, I read a book called "Microbe Hunters" by Paul DeKruif.

It was all about the history of the discovery of the germ theory and vaccinations and immunology and all that. Fascinating.
The Author devoted a chapter to Von Leewenhouk, who not only discovered sperm but microorganisms in general...Looking at pond water and all that.
Of course, they had no idea of the role of these creatures in disease.

Jul. 02 2016 03:10 PM
isaac from Brevard, NC

I enjoyed listening to this episode and I learned more about sperm

Dec. 04 2014 11:14 PM

In the words of Todd Akin: "If it's a legitimate rape, the female body has ways to try to shut that whole thing down."

He was right! About ducks.

Feb. 18 2014 02:19 PM
coop alan

If ants are related to bee's Then Sperm must be related to comets!!!???

Jul. 06 2013 05:06 PM

Someone left a comment here stating that Sperm are not souls. She was concerned that the radical right would use the fact of a sperm being or possessing a soul to bolster anti abortion arguments. Unfortunately her denial of the possibility that a sperm may be capable of a spiritual life, whatever that might mean, is a disservice to her own cause. She is committing the ages old crime of stripping consciousness from another life form merely to accommodate her own philosophical and political interests. Sperm, like all living organisms, are part of the same vast eternal web of life that includes everything on Earth from bacteria to to broccoli to blue whales. People foolishly chose to arbitrarily exclude specific manifestations of this mysterious universal entity that is life. Is a tsetse fly any less remarkable and unfathomable than a cheetah? Is a Giant Sequoia any less worthy of respect than a Senior Partner in a prestigious law firm? Well, I'm just saying that if we have a right to cut flowers into bouquets or fry fish on Friday then maybe we also have the same right to abort babies, regardless of their preeminent position on the biological pyramid that describes most people's conception of life.

Feb. 17 2013 09:17 AM
Susan Brown from Massachusetts

Really fascinating and well done. However, sperm aren't souls. And to confuse that is dangerous. It will lead to wiping out our sadly under attack, rights to abortion and birth control. Those are still rights and some of us care greatly about them. Babies are a joy and treasure but need to remain a choice. Let's not bring religion into this. That's a personal choice as well and should remain that way.

Aug. 11 2012 03:45 PM
reed cooper

Here's why it takes just one egg, but so many sperm to make a human baby:

Because men don't like asking for directions.

Nov. 03 2011 11:14 PM
Amy Eden from Petaluma, California

The editing was great. I listened to this driving from SF back up to Petaluma, and the humor mixed with the energetic editing truly worked. I laughed out loud several times ('what's with all the British people?' etc. Loved it).
The young woman's story provided a human touch and good contrast to the more clinical aspects. Of course I wanted her to find her dad - but, you know, that she didn't made it's own point. Great program. Thanks!

Nov. 03 2011 12:23 AM
Michael Schneider from Pittsburgh

in re Anton Van Leewenhoek, I heard part of this segment, and someone said he was a draper (cloth merchant) and microscopes were his hobby. Yes, but . . . Lenses to checkout the thread-count of fabric were an important part of being a fabric merchant, and that's where his interest in making lenses came from . . . He just happened be very good at it, and -- some believe -- he found a way to make a bubble as part of blowing hot glass that had remarkable magnifying power & kept it secret . . . only recently has it been reproduced. Read the wikipedia article & follow the citations.

Mike Schneider

Sep. 12 2011 03:37 PM
Jane Lapham from Long Beach, CA

I came to the comments section hoping that I could info on the song played about 20 minutes into the episode... There it was!

Thank you!

Jun. 02 2010 06:42 PM
Ashwini from Usually NYC, but right now rural India

I thought the segment about the woman searching for her biological father revealed a sad fact about our society, which is that we define family through our biology or "bloodline" rather than the relationships we have with each other. I understand her desire to find the biological father, but it has become an unhealthy obsession for her. I think that if there weren't the stigma associated with being adopted or otherwise not biologically related to your family members, she wouldn't necessarily "see a stranger" when she looked in the mirror, as she stated. She would see that she was the child of two (I'm assuming) loving parents, whose qualification for being her parents was that they cared for her from birth. I wish the segment had explored this aspect as well.

Apr. 07 2010 05:09 AM

I have to disagree with ligeti42. I thought the story about the girl looking for her father was incredibly touching and the editing is really dynamic.

Great episode!

Nov. 16 2009 06:31 PM
Tom Niemisto from New York

I saw this new site and it made me think of the sperm episode.

Apr. 01 2009 12:43 PM
Owen Miller from Providence, RI

As always, great show. My brother (who went to Oberlin) got me hooked. However, I noticed a misnomer in the first part of the show. The man who discovered the wonderful penis-scooper of the damselfly (similar to the dragonfly) was Jon, not Jeff, Waage. As a student of his, I was excited to hear about him, and I had to write something!

Mar. 31 2009 05:33 PM
laura from Baton Rouge, LA

The first part of the episode (Why So Many?) is fantastic. Loved it. Not so much the other two...human interest stories are great and all, but This American Life's got that covered. I turn to you all when I want my mind to be blown. And you almost always deliver. Thank you!

p.s. as for the editing, I love it.

Feb. 04 2009 09:56 AM
Kristy Huljak from Cincinnati, OH

I'm a big NPR fan, but this was the first Radio Lab I've heard. It was very interesting, funny, heartwarming - I loved it! I'll be back on the dial next weekend and I've forwarded the link to many friends!

Jan. 11 2009 10:24 PM
Jason Sullivan from Richmond, VA

I too came here to find out who was responsible for that amazing Spanish language song about 20 min in. Thanks, Lulu -- I'm now a Juana Molina fan!

Dec. 15 2008 11:26 AM
Eric from Houston

Really enjoyed the episode, glad to know I wasn't the only one interested in finding out who that one artist was and somebody did my work for me!

Dec. 10 2008 04:39 PM
Todd Nadenichek from Chicago

Hi. What's the song about 3:30 into the podcast? It's some kind of a men's choir. Have you folks considered listing the music that you use in each episode, if it's available? thanks so much.

Dec. 10 2008 12:25 PM
Eric from Madison, WI

Just checked out Jauna Molina thanks to these comments. She has an incredible sound. Thanks for the tip!

Dec. 04 2008 06:06 PM
Lulu from WNYC

Hi Laura + Jason. The song is “Salvese Quien Pueda (Juana’s Epic Re-Version)” by Juana Molina. She's amazing!

Dec. 03 2008 02:43 PM
Laura Germano from Jacksonville, FL

Another interesting journey - like Jason from D.C., I was interested to know the music played during this podcast. Thanks

Dec. 02 2008 10:39 PM
Jason from D.C.

What's the song played about 20 minutes into the episode? Thanks.

Nov. 28 2008 03:01 PM

I'm sorry, but the interminable story of a girl seeking her biological father is just pathetic. And it ends with a schmaltzy song? What are we supposed to learn from this? And for god's sake, please let up on the hyperediting... Give your audience some room to imagine things for themselves. Seriously.

Nov. 26 2008 11:44 PM
Lulu from WNYC


The whole episode will be podcast on December 2. The podcast you heard was a little "sperm preview" shorty podcast. But until then, you can hear it as streaming audio right here on this page!

many thanks!

Nov. 25 2008 03:50 PM
J Ong from 10007

I enjoyed listening to this episode and went to the podcast on iTunes to hear it again. To my dismay, it's truncated, only about ten minutes long. Can somebody please correct this?

Thank you very much.

Nov. 25 2008 03:12 PM

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