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Trick5 – The 'DNA App for Couples' Knows My Kids’ Hair Color – Trick5

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Trick5 – The 'DNA App for Couples' Knows My Kids’ Hair Color – Trick5

In science, replication is important. One experiment can be a fluke, but if you get the same results over and over, you know you’re getting close to the truth. So when a DNA app called BabyGlimpse said it could predict what my children would look like, I was ready. I have three children, so I could check their results in triplicate.

How It Works

Helix seems to keep a pretty tight leash on the claims its partners can make. So you won’t find any outright pseudoscience, but you may well find things that are based on weak or partial evidence from the scientific literature.

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Even though Helix sequences large portions of your genome, the analysis from partners like BabyGlimpse works the same way as genotyping services like 23and me. They look through your DNA for specific single letters that have been identified in scientific studies as correlated with certain traits. For example, Europeans with two cytosines (“CC”) at a location called rs4988235 tend to be lactose intolerant. But there’s uncertainty here: it’s possible to be lactose intolerant without this variation, and this marker has no predictive value if your ancestors weren’t European.

So even for the simple traits like lactose intolerance, you have to take your results with a grain of salt. BabyGlimpse reports that my husband and I are probably both tolerant of lactose and can drink all the milk we want; our children probably will be, too. (They are fine with milk, but they’re also too young to know for sure. Even lactose-intolerant kids tend not to show symptoms at first.)

But nobody is sending their spit away for a romantic evening of finding out whether their kids are going to be lactose intolerant. The company’s screenshots emphasize hair and eye color and the idea that you can get a glimpse, right? of your future baby.

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What I Learned

Before my husband’s results came in, I was able to browse my own. I have a 68 percent chance of having brown hair, the app guessed. That’s correct—I was blond as a kid but I have brown hair now. It was wrong about my eyes though: its prediction was blue, with only a 27 percent chance of my real color, something in the hazel/green family.

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When my husband’s results came in, they said he has brown hair and brown eyes (yep), and according to the app, our children probably will too. That’s a win: all three of my kids fit that description.

There isn’t a single DNA marker for hair or eye color, since many genes are involved in creating a brown pigment and transporting it to the right places. So BabyGlimpse calculates a score based on several different DNA markers.

But the best part is that they put the uncertainty in context. Few traits are purely genetic; it’s almost always possible that something in your diet, upbringing, prenatal experiences, or something we haven’t yet discovered plays a role. There may also be an element of pure luck. In the case of hair color, BabyGlimpse says this trait is 86 percent due to genetics, and the markers they use can explain around 70 to 80 percent of that. Eye color is 96 percent genetic, the app says, with the markers covering 80 to 90 percent of that. Once of the papers they cite says this level of prediction is possible for people from across the globe, making it more useful as a predictor than the lactose intolerance marker that only says anything about Europeans.

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My husband tans fairly well and has slightly darker skin than me, but our results labeled him as having “very light” skin, with the kids and me having “light” skin. I don’t know what the difference between those is supposed to be, but okay.

Height didn’t seem to check out. BabyGlimpse said that I was taller than average, and my husband shorter. According to this calculator we’re both above average, him more so than me. Anyway, our kids are supposed to be on the tall side, and that more or less checks out.

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The prediction for hair curliness was off, but it also lacked information. Instead of a breakdown for probabilities of straight, wavy, and curly, it just said that we and our children would all have “wavy” hair. That’s true of me and one of the kids. My husband and one of my sons have very curly hair, and the third kid’s hair is too short to tell. BabyGlimpse admits that the known DNA variations only cover a “relatively low proportion (~20-50%)” of the variability in hair curliness. So this isn’t a particularly useful test.

There’s a prediction for male pattern baldness, which is not exactly a trait we look for in babies. To be fair, all of these traits are about a person’s appearance as an adult. Plenty of newborns have blond hair and blue or gray eyes, and are very, very short. So this doesn’t really give you a mental picture of your baby, but more of what to expect in another 20 years or more, long after you’ve forgotten about your BabyGlimpse results.

[results table TK]

Things get a little weirder when you get to the “just for fun” category. Based on one measly marker that was tested in elite athletes, BabyGlimpse describes our children’s “muscle fiber type” as “normal muscle composition. Gonna have to work hard (like most of us).” Call me skeptical (who, me?) but I don’t think this is a very helpful result. Especially when they acknowledge—or perhaps guess—that this marker explains less than 5 percent of the genetics at play.

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Our children are also likely to have a slight sweet tooth, according to BabyGlimpse’s interpretation of just one marker. They will also have the personality of either a “strategist” or a “mixed warrior-strategist” according to another tiny variation. According to SNPedia, which I’m using for the links for these markers, 23andme describes the dichotomy as “worrier” versus “warrior.” In any case, I really don’t think my kid’s personality is determined by one nucleotide.

BabyGlimpse, to their credit, keeps personality in the “just for fun” section of the app and indicates that the marker they test only explains “around 1%” of the known genetic variation, which is only 60 percent of the total variation. But then, if you know a result only explains 0.6 percent of the trait you’re talking about, what’s the point?

What We Got Out of This

BabyGlimpse is right to market itself as just for entertainment; I can’t think of a single meaningful decision I would make based on these results, and that’s probably for the best. But what would we have done without it? We’d probably have figured that our kids would have brown hair and brown eyes and light skin, and we’d still have no idea if they would turn out to be “warriors” or “strategists” or elite athletes.

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So, we learned nothing. But it was kind of fun? And now we can blame the kids’ DNA (which really means blaming ourselves) when they share our sweet tooth. Then again, we were doing that anyway.


Trick5 – The 'DNA App for Couples' Knows My Kids’ Hair Color – Trick5

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