How Three People Can Make a Baby - and Why It Matters
Last night, I had intriguing conversations with biotech scientists and a journalist at the DeSci event. Among topics like cultivated meat, blood transfusion, and reproductive technology, what fascinated me most was a baby with DNA from three people.
The basic idea is to use two eggs—one from the mother and one from the donor—remove the nucleus from the donor’s egg, inject the mother’s nucleus into it, and then fertilize it with the father’s sperm. At first, this seemed confusing to me—if the genome is stored in the nucleus, how could the embryo contain DNA from three people?
Curious to learn more, I looked into it when I got home. I found that the BBC reported in 2023 that a baby has been born using the DNA of three people for the first time in the UK. However, this wasn’t a groundbreaking first—the first known case was actually reported in 2016.
Initially, I thought this was another crazy trend, but this technology, mitochondrial donation treatment, is actually an attempt to prevent children from being born with devastating mitochondrial diseases. These incurable diseases can be fatal within hours or days of birth. For some families, like the woman who tragically lost seven children to mitochondrial disease, this technique offers hope for a healthy child.
To address this issue, scientists developed a specialized form of in vitro fertilization (IVF). The goal is to replace faulty mitochondria in a mother’s egg with healthy mitochondria from a donor.
The most commonly used method for mitochondrial donation is maternal spindle transfer, which repairs the egg before fertilization.1 Scientists first retrieve an egg from the mother, which contains faulty mitochondria, and carefully extract its nucleus. They then take a healthy donor egg, remove its nucleus, and discard it, leaving behind only the donor’s mitochondria. Finally, the mother’s nucleus is inserted into the enucleated donor egg, creating a reconstructed egg with her nuclear genetic material but healthy mitochondria. This egg is then fertilized with the father’s sperm, resulting in an embryo free from mitochondrial disease.
But what does this mean for the baby’s DNA—does it truly come from three people?
The answer lies in mitochondrial DNA (mtDNA), which actually makes up about 0.1% of our genome. While nearly all genetic material comes from the parents, mitochondria contain their own small set of DNA, inherited exclusively from the mother. When a donor provides healthy mitochondria, the baby inherits this tiny fraction (~0.1%) of DNA from a third person. However, since mitochondrial DNA only affects cellular energy production, it does not influence traits like appearance, personality, or intelligence. In essence, the donor’s contribution is solely to ensure the baby’s mitochondria function properly, preventing disease while leaving everything else unchanged.
Mitochondrial diseases are passed down only by the mother.↩︎
Why Antibiotics in Animal Farming Are a Ticking Time Bomb
The fear of the COVID-19 pandemic is still fresh in our minds. Everybody would agree that we want to do the best we can to prevent the next pandemic. One major source of the next pandemic is industrial animal farming, where antibiotics are overused. They use antibiotics to prevent disease, treat infections, and promote faster growth. In the 2010s, around 70% of antibiotics used globally were given to farm animals, and there is no evidence that usage has declined.
Antibiotics fight bacteria by killing them or stopping their growth, helping the body heal. However, overuse leads to resistance, allowing bacteria to survive treatments, spread easily, and leave fewer effective options for fighting infections. Resistant strains from livestock can transfer to humans, making illnesses harder to treat and posing a major health risk.
In fact, drug-resistant bacteria like Salmonella, E. coli, and Campylobacter have caused major outbreaks. For instance, multiple antibiotic-resistant strains of Salmonella Heidelberg triggered large U.S. outbreaks in the 2010s, infecting thousands through contaminated chicken products.
This is another reason why alternative proteins, whether plant-based, fermentation-derived, or cultivated, are a better option. They make it easier to maintain a sterile environment, reducing the risk of bacterial contamination and antibiotic resistance.
Brief Chemistry of Msg
Scientific research today is crystal-clear: MSG is safe. Let me explain why.
MSG is the sodium salt of glutamic acid. When it dissolves in water, it separates into sodium and glutamate ions. Sodium itself is an essential mineral for life and is not inherently harmful; in fact, table salt contains three times more sodium than MSG. Meanwhile, glutamate is naturally present in many foods, including konbu, meat, fish, eggs, kelp, tomatoes, cheese, and mushrooms. Importantly, your body processes glutamate from MSG in the same way it metabolizes glutamate from these foods, as the glutamate in MSG is chemically identical to that found in nature. Given this, consuming MSG is no different from consuming foods that contain glutamate. If MSG were inherently harmful, then all glutamate-containing foods would have to be considered harmful as well—a claim that is not supported by science.
Umami Unleashed - Dispelling Msg Myths
When I moved to San Francisco, I noticed something interesting in supermarkets: many food packages were labeled “No MSG.”
This stood out to me because I had never seen such labels in Japan, where I am from. Intrigued, I began to wonder what MSG is and why it’s perceived as harmful.
As I looked into it, I learned that monosodium glutamate (MSG) is a flavor enhancer first commercialized by a Japanese company, Ajinomoto, and it is commonly added to canned vegetables, soups, and processed meats. More importantly, I discovered that the U.S. Food and Drug Administration (FDA) classifies MSG as “generally recognized as safe,” placing it in the same category as salt and pepper. This means that, based on scientific evidence, MSG is safe to consume in normal amounts.
But if MSG is scientifically considered safe, why do so many food packages proudly advertise “No MSG”? You rarely see labels boasting “No Salt” or “No Pepper.” If companies are using this label to appeal to consumers, what is driving the demand to avoid MSG in the first place?
To understand this skepticism, I looked into the history of MSG skepticism. In the 1960s, a small number of Americans who ate Chinese food reported experiencing symptoms such as drowsiness, facial flushing, itching, headaches, body numbness, and mild back discomfort. These symptoms were collectively dubbed “Chinese Restaurant Syndrome” after Robert Ho Man Kwok published a letter with the same name in the New England Journal of Medicine in 1968.
Notably, this wasn’t a formal scientific research paper—it was just a anecdotal letter to the editor describing these symptoms. Still, its publication seems to have sparked widespread suspicion about MSG. The following year, The New York Times published a report linking MSG to Chinese Restaurant Syndrome, further amplifying public concern.
Despite subsequent scientific studies debunking the association between MSG and these symptoms, the negative perception persisted. Even today, many people instinctively distrust MSG, even though there is no solid evidence to support these fears.
Many argue that the MSG myth is rooted in racism, but it is bigger than that. Interestingly, skepticism about MSG is not a recent or American phenomenon. Misinformation about it has circulated for over a century—even in Japan, where MSG was first discovered by the chemist Kikunae Ikeda and commercialized by Ajinomoto.
An example of this dates back to an opinion advertisement published on May 13, 1922, in the Tokyo Asahi Paper. Issued under the name of Suzuki Shoten, the predecessor of Ajinomoto, the ad stated: “We declare to the world that Ajinomoto is absolutely not made from snakes.” This was a direct response to misinformation claiming that their MSG product was derived from snakes.
This pattern of consumer misconceptions raises a deeper question: why do people keep making the same mistake for over 100 years?
Reflecting on this, I realized it might stem from the naturalistic fallacy, a concept I’ve mentioned before. People often distrust additives because they perceive them as “unnatural” and therefore harmful.
But where does this deep-rooted preference for “natural” foods come from? One possible explanation is the historical backlash against industrial pollution.
I’ve previously discussed examples like DDT, asbestos, and lead-based paints, which contributed to widespread distrust of industrial chemicals. In Japan, a 1973 investigation by the Kawasaki City Pollution Control Bureau found that Ajinomoto, among other factories, had been discharging mercury into Tokyo Bay at dangerously high levels. At the same time, the company was also involved in producing and selling DDT, a synthetic pesticide widely used after World War II. Cases like these reinforced the idea that anything industrial or synthetic must be dangerous, especially when the company has been involved in the industrial pollution in the past.
In reality, the fear of food additives isn’t rooted in science—it’s tradition. My mother warned me about them, just as many parents do, passing down skepticism without question. But “natural” isn’t always better, and progress has made food safer, not riskier.
MSG’s story is a reminder of how old fears outlive the facts—and how deeply ingrained beliefs can shape our choices, even when the evidence says otherwise.
Could You Game a Lottery?
Late last year, I joined this advantage gambling event out of curiosity about how the world depicted in the movie 21 operates in real life. The speaker covered various games and strategies to exploit them. The biggest surprise came when he discussed lotteries. I had always thought lotteries were only for idiots since the expected value should be negative.
Expected value (EV) is calculated as (Reward * Probability) - (Penalty * Probability). In the case of a lottery, it represents the chance of winning multiplied by the prize, minus the ticket price.
How can you have a positive expected value (EV) in lotteries? You won’t achieve this by purchasing your tickets early. However, as more tickets are sold and prizes are distributed, there may come a time when the EV becomes positive because the probability of winning might increase with enough prizes remaining.
How do you get information about the prize and probability? Apparently, lottery players scrape lottery websites to fetch this information and then calculate the EV. This repo parses scratch-off lottery ticket data from state lottery websites, for example. The EV calculation has to be more complex than this repo’s calculation when you consider things like taxes and multiple winners (you might have to split the prize), but it’s certainly doable if you are willing to put in some effort.
In practice, prize distributions may be designed in a way that you can’t beat the system, and the logistics can be challenging. But still, buying a lottery ticket may not be idiotic when you figure that the EV is positive.
The Habsburg Curse - Recessive Genes and the Doom of Royal Inbreeding
Carlos II was born into the Habsburg family, a dynasty that had ruled Spain for centuries. He suffered from numerous severe physical and mental health issues, including developmental delays, infertility, premature aging, frequent convulsions, and chronic gastrointestinal problems.
Notably, his oversized jaw, a hallmark of the Habsburg lineage, made eating and speaking particularly difficult for him.
These weren’t just random bad luck; it is said that they were due to the Habsburgs’ habit of inter-family breeding. This was supposed to keep their royal bloodline pure, but it ended up causing its downfall. Carlos II was the last of the Spanish Habsburgs, marking the end of their rule.
It’s common sense that inter-family breeding, also known as consanguineous marriage, is a bad idea. But why?
Consanguineous marriage can increase the risk of certain genetic disorders due to the inheritance of recessive genes. Genes can be either “strong” (dominant) or “weak” (recessive). If you have a dominant version, that’s the one that gets expressed, even if you also have a recessive version. The recessive gene will only be expressed if you inherit two copies of it—one from each parent.
For example, think of eye color. If brown eyes (dominant) and blue eyes (recessive) are options, you’ll have brown eyes if you inherit one brown-eye gene because brown is stronger. To have blue eyes, you need to inherit the blue-eye gene from both parents, because two recessive genes are needed for it to show up.
In consanguineous marriages, because the parents are related, they are more likely to both carry the same recessive genes, so the chances of their children inheriting two recessive versions are higher.
Inheriting two recessive versions of a gene isn’t always a problem. However, some recessive genes carry instructions that don’t work properly, and if a child inherits two copies of a recessive gene mutation, it can lead to health issues.
For example, Cystic fibrosis (CF) and sickle cell disease are genetic conditions caused by inheriting two faulty copies of recessive genes.
Although not all of Carlos II’s health conditions may not come from detrimental recessive genes, scientists from Spain’s University of Santiago de Compostela argue that his conditions such as muscular weakness, willpower deficiency, infertility/impotence are likely to come from his genetic disorder.