Breeding Between the Lines

Breeding Between the Lines

Race in America is a controversial topic. And interracial love has long been considered the ultimate taboo. For a country that prides itself on being a melting pot, we've done very little melting. For legal, societal, and cultural reasons, intermarriage rates in the US have always been extremely low. Until now.

Alon Ziv has long predicted that America is on the cusp of a mixed-race explosion. Now, in this expanded new edition of Breeding Between the Lines, he shows that the explosion is well underway. As our interracial population skyrockets, America is finally becoming a true melting pot. The book explores what this means for the millions of interracial Americans who benefit from increased genetic diversity and for our nation as a whole.

Though many people still focus on the potential negatives of interracial relationships — the prejudice that the couple and their children will face, the conflicts of two different worlds, identity issues — those are only part of the story. Breeding Between the Lines is the first book to shine a light on the significant biological advantages of interracial unions.

Mixed parents give their children the precious gift of diverse DNA. Their blended heritage protects interracial people from common genetic disorders like sickle-cell anemia and cystic fibrosis. But that's just a small part of the power of genetic diversity. Recent research at UCLA and Penn State University found that because of this genetic variation, interracial people are significantly healthier and more attractive than people with homogeneous backgrounds.

The biology of race is a sensitive topic with an ugly history, but Breeding Between the Lines approaches it responsibly. The book is based on hundreds of peer-reviewed studies from scientists all over the globe. Ziv presents evidence from academic journals, world history, census counts, and pop culture to explain why interracial individuals have measurable physical and mental advantages.

From the sex lives of bedbugs to the remarkable feats of professional athletes, he illustrates how biology influences every aspect of our lives and how the right combination of genes can make all the difference. The book also addresses why we choose the mates we do. Why, in the past, brides and grooms looked more similar than different. And why this is all changing.

alon ziv

Alon Ziv

Alon Ziv has been writing and lecturing on the biology of interracial people for over 10 years. He’s appeared on the BBC London Evening News, the KTLA Morning News, Air America, BBC Radio, and local radio across the United States. He has spoken on the science of interracial mixing for the Biracial Family Network, the Hapa Issues Forum, the Multicultural Resource Center at Penn State, and other organizations and colleges across the country. He was awarded the Certificate of Distinction in Teaching in Biology from UCLA. He lives in Los Angeles. And no, he is not interracial.

Frequently Asked Questions

If you have any questions that aren't answered here, they're probably addressed in the book. You can also send me an email.

What kind of science is the book based on?

Breeding Between the Lines is based on hundreds of studies from academic journals in evolutionary biology, biochemistry, animal behavior, botany, anthropology, human diversity, and medical genetics. There is a full set of notes and references in the back of the book.

Are you advocating eugenics?

Not at all. For one, Breeding Between the Lines is not an instruction manual. I encourage people to marry whomever they want. Secondly, eugenics historically argued for the exact opposite of interracial unions. Racist eugenicists were attempting to create some kind of "pure" race. Breeding Between the Lines shows why this type of institutionalized inbreeding is a very bad idea.

Isn't race just a social construct?

Short answer: No. Race obviously has social elements, but it's silly to deny that it has biological underpinnings. Rachel Dolezal thought that race was just a social construct. It did not work out well for her.

Long answer: Chapter 4 of Breeding Between the Lines is the long answer to this question. I give an in-depth explanation of the biological basis of race. I also discuss the limitations of race from a biological perspective, since racial categories are overlapping and tricky to define. Finally, I talk about why the biology of race is so scary and why we want race to be a social construct.


Reddit AMA

Friday April 29, 2016 at 11am Pacific
username: alphazulu0

Airtalk with Larry Mantle, KPCC 89.3 FM

Tuesday March 29, 2016 at 11:40am
Southern California Public Radio

Books Circle Online

Wednesday March 30, 2016

Official Book Launch Party and Signing

Sunday May 15, 2016 at 3pm
Diesel Bookstore
Brentwood Country Mart
225 26th Street, Suite #33
Santa Monica CA 90402


The David Pakman Show

Book Circle Online

AirTalk with Larry Mantle, KPCC FM

Listen to Alon on AirTalk with Larry Mantle

KTLA Morning News

The Kevin & Bean Show, KROQ FM

Listen to Alon on the Kevin & Bean Show

The John Zeigler Show, KFI AM

Listen to Alon on the John Zeigler Show

Is It Better to Be Mixed Race?

A British documentary based on Breeding Between the Lines.

Buy the Book

"I suggest people read this book... it'll get you thinking."

Michaela Pereira, KTLA Morning News

"Very interesting... and very relevant."

John Ziegler, The John Ziegler Show, KFI AM

“Only a Jew would say such things. . . . Another attempt to mongrelize the white race by a filthy Lieing Jew.”

Random White Supremacist, The Internet
(White supremacists are terrible spellers and they hate me! Yet another reason to buy Breeding Between the Lines.)


East Marries West

Hawaii has always been a meeting point between East and West. This tropical paradise has no ethnic majority; its two biggest minorities are Asian-Americans and European-Americans. Possibly because of its tremendous ethnic diversity (or because of the abundance of piña-coladas), Hawaii has the highest rate of intermarriage of any state in the union. According to the 2000 Census, an incredible 21.4% of Hawaiians identify themselves as belonging to two or more ethnic groups. Hawaii is a true melting pot.

So when scientists did a study in Hawaii on the genetics of intelligence they were guaranteed to run into some interracial individuals. They focused their research on Americans of European Ancestry (AEA) and Americans of Japanese Ancestry (AJA), but some of their participants were both. The researchers administered a battery of 15 cognitive tests designed to measure intelligence. All of the groups had a similar socioeconomic background. But the biracial, half-European/half-Japanese participants outscored both the AEA group and the AJA group on 13 of the 15 tests.

You Really Are Smarter than Your Parents

The cognitive performance of the biracial group is impressive and it may hold the key to a long standing mystery. For some reason, we seem to be getting smarter. No one is sure why, but the average IQ score has consistently been creeping up by about 3 points every 10 years. This implies that each generation is significantly smarter than the previous one.

The phenomenon, known as the Flynn Effect, after its discoverer, has been seen all over the world. The effect is commonly believed to be caused by some kind of environmental factor. The most popular theory is better nutrition. Remember how your mom always told you to eat a good breakfast before a big test? Even though she came from a dumber generation, she was right. Better nutrition does lead to improved physical and mental development. But at the same time, nutrition can only go so far. And the link between nutrition and the Flynn Effect is somewhat shaky. The effect was stronger than ever in Scandinavia in the years following World War II, even though during the Nazi occupation, food was almost as scarce as freedom.

At least one intelligence expert thinks that the cause isn't environmental at all - it's hybrid vigor. True interracial marriage is still relatively rare, but the world is a smaller place than it's ever been. People are less and less likely to marry someone from their own village. Plus, increased immigration and the growth of large cities mean that even if you marry the boy or girl next door, they may be ethnically very different from you. So, even if people are marrying within their race, they are still probably producing children with higher heterozysogity than the previous generation. That higher level of heterozygosity may account for the mysterious IQ boost.

The average height and growth rate have also increased significantly over the past few generations. Just as with intelligence, better nutrition usually gets all of the credit. Certainly, nutrition is a factor though I don't think it's the whole story. It wasn't long ago that diseases like Scurvy and Beriberi were significant public health problems. Scurvy is caused by a lack of vitamin C and sufferers complain of weakness, bruising, and bleeding gums. A diet without fresh fruit or greens can lead to Scurvy. Beriberi is caused by a deficiency in vitamin B1 (thiamine). People with Beriberi suffer from extreme weakness and heart problems. It can be fatal. The name Beriberi comes from the Sinhalese language (spoken in Sri Lanka) and means, "I cannot. I cannot."

Nutritional deficiencies like these are still a problem in some parts of the world, but they have mostly been conquered in first world countries. When was the last time you called in sick because of a bad case of Scurvy? Certainly nutrition has significantly improved over the last few hundred years. I have no doubt that it is a big part of the gains in intelligence, height, and growth rate that have been recorded. But I believe that hybrid vigor is another important component of these improvements.

As the world has become a smaller place, people have more choices of marriage partner. Most of us are no longer limited to the population of our village. Even though a majority of us are still marrying people from the same ethnic group, we are mixing genes more than ever before. When my friend Lorna, whose grandparents were Italian immigrants, married Stefan, who is of Swedish extraction, it was hardly scandalous. To most people they both just seem "white." But this is a pairing that was geographically and socially unlikely in previous generations. They are more genetically distinct than an Italian-Italian or a Swedish-Swedish couple would be, and their kids will benefit from increased heterozygosity.

I see this as the first phase of human hybrid vigor. And I think it's at least partially responsible for the Flynn Effect as well as other modern day improvements. But by introducing even more genetic variation, we can go even further. Once true interracial marriage becomes commonplace, I think we'll see an even bigger boost in the physical and mental development of future generations. I find this thought incredibly exciting. I like the idea that with everything that we've achieved as a species, we can still do better. We can still do more. We have enormous potential lying untapped in our DNA, just waiting to be released. It's also rather poetic that after every inappropriate racist joke, hurtful cultural slur, destructive race riot, and horrible ethnic cleansing, the key to so much lies in embracing our differences. It's ironic and sad that wars are still being fought over ethnic divides, when everything you could ever wish for your children - health, beauty, intelligence - is buried inside the cells of your enemy.

Why did the interracial Hawaiians dominate the intelligence study? Buy the book and find out.