The Trouble with (and without) Fish

Once upon a time in a vast ocean, life evolved. And then, over many millions of years, neurons and spinal cords and eyes developed, nourished all the while in a gentle bath of nutrients and algae.

Our brains and eyes are distant descendants of those early nervous systems formed in the sea. And even though our ancestors eventually sprouted legs and waddled out of the ocean, the neural circuitry of modern humans is still dependent on certain nutrients that their water-logged predecessors had in abundance.

This obscure fact about a distant evolution has recently turned into a major annoyance for me now that I’m pregnant. In fact, whether they know it or not, all pregnant women are trapped in a no-win dilemma over what they put into their stomachs. Take, for instance, a popular guidebook for pregnant women. On one page, it advocates eating lots of seafood while pregnant, explaining that fish contain key nutrients that the developing eyes and brains of the fetus will need. A few pages later, however, the author warns that seafood contains methylmercury, a neurotoxic pollutant, and that fish intake should be strictly curtailed. What is a well-meaning pregnant lady to do?

On a visceral level, nothing sounds worse than poisoning your child with mercury, and so many women reduce their seafood intake while pregnant. I have spoken with women who cut all seafood out of their diet while pregnant, for fear that a little exposure could prove to be too much. They had good reason to be worried. Extreme methylmercury poisoning episodes in Japan and Iraq in past decades have shown that excessive methylmercury intake during pregnancy can cause developmental delays, deafness, blindness, and seizures in the babies exposed.

But what happens if pregnant women eliminate seafood from their diet altogether? Without careful supplementation of vital nutrients found in marine ecosystems, children face neural setbacks or developmental delays on a massive scale. Consider deficiencies in iodine, a key nutrient readily found in seafood. Its scarcity in the modern land-based diet was causing mental retardation in children – and sparked the creation of iodized salt (salt supplemented with iodine) to ensure that the nutritional need was met.

Perhaps the hardest nutrient to get without seafood is an omega-3 fatty acid known as DHA. In recent years, scientists have learned that this particular fatty acid is essential for proper brain development and functioning, yet it is almost impossible to get from non-aquatic dietary sources. At the grocery store, you’ll find vegetarian products that claim to fill those needs by supplying the biochemical precursor to DHA (found in flaxseed, walnuts, and soybean oils), but we now know that the precursor simply won’t cut it. Our bodies are remarkably slow at synthesizing DHA from its precursor. In fact, we burn the vast majority of the precursor for energy before we have the chance to convert it to DHA.

So pregnant women must eat food from marine sources if they are to meet all the needs of their growing babies. Yet thanks to global practices of burning coal and disposing of industrial and medical waste, any seafood women eat will expose their offspring to some amount of methylmercury. There’s no simple solution to this problem, although recent studies suggest that child outcomes are best when women consume ample seafood while avoiding species with higher levels of methylmercury (such as shark, tilefish, walleye, pike, and some types of tuna). Of course much is still unknown. Exactly how much DHA intake is enough? And since mercury levels vary based on where the fish was caught and what waste was released nearby, you can never be sure it’s safe to eat.

Unless we start cleaning up our oceans, pregnant women will continue to face this awful decision each time they sit down at the dinner table. Far worse, we may face future generations with lower IQs and developmental delays regardless of which choice their mothers make. Thanks to shoddy environmental oversight, we may be saddling our children with brains that don’t work as well as our own. And that is something I truly can’t swallow.

Guessing at Sex

Something’s happened. Something both miraculous and mundane. Over the past few months I’ve been transformed from a woman into an incubator. A walking, talking (and often eating and napping) incubator programmed to provide the perfect environment for a growing baby . . . something. We’ll find out the gender in a couple weeks. Still, it’s always the first question people ask when they hear that I’m pregnant: “Is it a boy or a girl?” And since we haven’t had an answer for them, my husband and I have been showered with an astonishing number of guesses. It seems that everyone we’ve ever met is secretly a gender-divining expert.

They all have their methods. One woman had me turn around so she could size up my back fat. “If you gain weight in the back, it means you’re having a boy,” she explained. Another examined my face as she explained her theory that women who carry a girl look more beautiful (thanks to the added female hormones) while those carrying a boy start looking more, well, dude-like. Others have sworn by the shape of the belly – if the stomach looks pointed versus broad. One acquaintance asked for the baby’s fetal heart rate, saying that babies with faster heart rates always turn out to be girls. Another friend described her theory that the mother’s personality predicts the baby’s sex; apparently, soft-spoken mothers tend to have boys.

I like when people guess the gender. It’s interesting to hear their varied theories and sweet to think that they’re excited enough about our pregnancy to venture a guess. It makes a personal, biological experience more communal. But I can’t say much for their accuracy. So far, the guesses have been evenly split between boy and girl.

That’s the thing about guessing gender; with a 50-50 chance of either outcome, it’s unimpressive if you’re right and even more unimpressive if you’re wrong. And yet with such odds, it’s only natural that people start thinking they’ve hit on a good heuristic. No matter how wrong your method, you will, on average, be right 50% of the time. That already subjectively feels like a lot of rightness. If you try your method out on a small number of people to start, you could wind up with a lower success rate (by chance) and perhaps abandon your technique, but you might luck out and guess right 75% of the time or higher, at least for a little while. Someone who starts out on a lucky streak may well become a diehard believer who swears by his method, even after his batting average declines.

There’s simply no way that so many people can be so sure of their gender-guessing strategies unless they pick and choose their outcomes. Or unless, as I suspect, their memories do it for them. Consider the conundrum of the grocery store line. Many of us believe we are cursed (or mysteriously inept) at choosing a checkout lane at the grocery store. No matter which line we wind up in, it turns out to be the slowest. If we switch to another, that one mysteriously slows down. You rarely hear about the reverse – people who claim to have a special gift for picking the fastest lane. How can the majority of people be below average at the same task? If their memories are skewing the results. We never notice and remember the times we breeze right through checkout or overtake our neighbors in the next line over. The salient events – and the ones we’ll remember – are the times we’ve been stuck behind someone arguing prices or heaping coupons on the counter. Times when six people go by in the next line over while your food wilts and thaws on the conveyor belt.

It must be the same with guessing gender. When people are right, they are ecstatic and vindicated. When they are wrong, they notice and remember it less. And those that do notice their error may wonder if they misjudged the belly shape or back fat. The problem wasn’t necessarily with the heuristic, but rather with its execution. If only the pregnant lady’s dress had been tighter or if the guesser hadn’t been distracted by hors d’oeuvres, the method would certainly have worked!

I am by no means immune to these twisted ways of thinking. I can’t help but believe that I’m cursed at picking grocery lines. And I also seem to have a guess about this baby’s gender. For no apparent reason, I have it in my head that the baby is a boy. No heuristic here, just a feeling I can’t seem to shake. It’s not that I’d prefer a boy – I’d be equally delighted to have a girl. And I know that there’s no scientific merit to the inkling. Even if a woman could tune into some subtle something in her body and know, she’d need prior experience to compare it to. This being my first pregnancy, I have no idea what it might feel like to carry a boy versus a girl, if such a thing were even possible. So I should put no stock in such a feeling.

And yet when the ultrasound rolls around, I know I’ll be surprised if we learn that the baby’s a girl. Equally happy and excited, to be sure. But most definitely (and illogically) surprised.

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