I began by looking to the stars—TV and movie stars, that is. A glitterati’s face is loaded with instances of a special kind of symmetry, called dynamic symmetry, which we recognize by instinct. The actor with “screen appeal,” the actress with “that certain something,” the up-and-coming journalist groomed for the anchor seat because of her “fresh” face, the photogenic author with the winsome smile—what we’re really talking about, here, is geometry. As we saw in Chapter 3, our brains are exquisitely sensitive pattern detectors, capable of assessing the architecture of a human face with NASA-like precision. And as NASA was reminded with Hubble, a hair’s breadth can make all the difference. Deviations of just a millimeter from the ideal create features that fail to align perfectly with Marquardt’s mask, and we can take all this information in instantaneously. We prefer to fix our gaze on faces with broad foreheads balanced by strong jaws, prominent brows above deep-set eyes framed with nice, high cheekbones—those are the characteristics which tend to bend the angles of the human face toward a more perfect proportionality. As you might have guessed, models and movie stars from Greta Garbo to Angelina Jolie have a habit of hoarding more than their share of dynamic symmetry. And often they are the first born of their family.
In contrast, their younger siblings’ faces are often noticeably less symmetrical. Most are characterized by a narrowing of the mid-portion of the face, rounded, indistinct features including noses, cheekbones and brows, and a weakening of the chin and jaw. Are A-list movie stars always the oldest child in the family? Certainly not. As you’ll see later, in the setting of maternal malnutrition, sometimes the uterus doesn’t work quite perfectly the first time around. But with few exceptions (notably, Tom Cruise), those who had older siblings had three or more years spaced between them.
Of course, superstar looks are rare (in the modernized world), and the chance for any family to produce even one stellar beauty is vanishingly small. The statistical improbability of one stunner following on the heels of another would predict, with rare exception, any consecutive child to be less attractive than the first. This would explain a fair, though miserly, rationing of young stars and starlets throughout the general population, but it would fail to account for the fact that the most attractive, most successful siblings are typically the oldest or, in families of three or more, one of the first two. It seemed to me that better nutrition was the simplest, most likely explanation for first-born children with favorable looks. But before exploring that further, I first wanted to see if the second sibling phenomenon could be found not just among the supermodels of society, but also among the rest of us in the general population.
So I expanded my research. With the generous help of office mates, patients who supplied stacks of high-school yearbooks from 1969 to 2006, and graduate students from the University of Hawaii, I compiled several hundred groups of siblings, cutting and pasting their senior photos (to control for age) and organized them in family groups. Some were large and some were small. But all the families included in the study had at least two siblings born within two years of each other. Just as with the celebrity siblings, among those pictured in the yearbooks, family beauty generally faded according to the same pattern: From oldest to youngest, the jaw grew narrower and receded, the cheekbones flattened out, and the eyes were less deeply set. The closer in age the siblings, the more striking the changes. But spacing alone does not prevent this effect. With anything short of an optimal dietary context, if mom’s body is asked to produce large numbers of children, then each subsequent baby uses up more of her reserves so that, even with three to four years between births, her body continues to lose nutritional ground. This can magnify the effects of second sibling syndrome down the line. The implications for the younger children are obvious.
There is, however, one additional twist on the second sibling syndrome worth mentioning—as I alluded to earlier. It seems to result not from nutrient deficiency per se, but from chemical interference (from sugar and vegetable oil) delaying signal transmission between mom’s body and her own uterus. Some second-born females have fuller lips and more sexually appropriate chins and eyebrows than their older siblings—a woman’s chin being a little more pointed, less squared, than a man’s, and a woman’s eyebrows being more arched while men’s are lower and straighter. The pointier female chin and gracefully curved eyebrows are examples of sexual dimorphism, the differential development between males and females. Human males, in addition to strong, squared chins, tend to have broad shoulders while women, with their more petite and rounded chins, also have slender shoulders, wider hips, and fatty breast tissue. So what would explain these second-born girls with the more attractive, sex-specific features?
A woman’s body undergoes a miraculous change soon after conception. Under the influence of a new physiologic directive, the functioning of every organ is altered by waves of hormones, all generated by the tiny collection of rapidly dividing cells. Many of these changes are permanent. Of course, no organ is affected more obviously than the uterus. But a modern diet interferes with hormonal signaling, as we’ll see later, so the uterus especially can’t perform quite so well, at least not at first. Blunted uterine (and placental) estrogen signals could explain why estrogen’s effects on a first baby girl appear diminished. Subdued estrogen effects lead to relatively masculine features: slightly too prominent brow and chin, aggressive-looking eyebrows, and lips not quite filled out. She may be handsome, but she won’t turn heads. With uterine systems already existing the second time around, estrogen’s effects are optimized. The first baby girl’s younger sister (Christy Turlington is a perfect example, see Figure 4), gifted with the similar bone structure but feminized and with the felicitous addition of full, rounded lips, will present a face whose image will leave men hopelessly enthralled, haunted by her image as if evolution had specifically wired them to be susceptible to its charms. Incidentally, if the second sibling were a boy, the burst of estrogen receptivity may still create a feminizing effect, sharpening the center of the chin, arching the eyebrows, rounding the forehead, and plumping the lips.
So what does this mean? Well for one thing, though the development of a beautiful, healthy baby is—as we are so fond of saying—miraculous, it’s not a mystery. This spectacular orchestration of events is as dependent upon a strict adherence to a program of good nutrition as it is vulnerable to its breach. Studying siblings enables us to see why we aren’t all perfect. It enables us to see that nutrient deficits change a child’s growth in ways that are both predictable and easy to measure. I call it second sibling syndrome not because it only affects second born children, but simply because the effects of maternal malnutrition on a child’s growth are most readily visible in the faces of children born in a short time period after an older sibling who, pre-sumably, shares similar genes and thus serves as a kind of control. But as I just described, no child, not even the firstborn, is immune from second sibling syndrome because the underlying problem is not birth order; it’s malnutrition. In the younger children, maternal nutrient deficiencies result in relatively less material to build bone, nerve, and so on, impairing hormonal receptivity and thinning and flattening their features to create a worn-down look. In the older children, static interference from sugar and vegetable oils often blunts placental hormone production, reducing sexual dimorphism.
If you read Chapter 4, then you already know that the vast majority of Americans—and I mean just about everyone—isn’t merely malnourished, but severely malnourished. Which should make you wonder: Doesn’t that mean we’re all suffering from second sibling syndrome? Most of us are, which is why there seems to be so few lottery winners walking around. And what explains them? How did they, raised by parents who, presumably, followed the same advice my parents did, and ate the same steady diet of frozen, canned and vitamin-poor fruits and vegetables, mystery meat from poisoned animals, grains grown on mineral depleted soils, margarine, and everything else that makes our modern diet unhealthy, curry Mother Nature’s favor? They didn’t. Their great-great grandparents did, by eating
such nutrient-rich diets that they imparted the family epigenome with genetic momentum, the ability of genes to perform well with suboptimal nutrient inputs for a finite amount of time. And their placentas did, by sending an especially urgent message to mother’s bones, brain, skin, muscles, glands and organs, to release every available raw material for the benefit of the baby. In these one-in-a- million cases, the fetal genome operating in mom’s belly can do what it’s been doing for a hundred thousand years: create the miracle of a perfectly symmetrical Homo sapiens body.