The PFC is the center of the “thinking” brain, and the amygdala (ah-MIG-di-lah) is a principle structure of the “feeling” brain. These two networks are seen as parallel systems whose integration evolves with time. The emotional system is present early in life; it’s fast and mostly automatic—what’s often called a gut reaction. The cognitive system develops with age, is slow and deliberate, and sometimes competes with the older system.61 It has been suggested that because the emotional system is more mature than the cognitive one in teens, it sometimes contributes more to decision-making, resulting in less-than-optimal choices.62
Dr. Laurence Steinberg, a nationally recognized expert in adolescent psychology at Temple University, draws a distinction between “cool” and “hot” conditions, referring to the intensity or level of emotion at the time a decision is made.63 Under “cool” conditions—a hypothetical dilemma in class, for example—a teen might appear to have excellent “executive functions”: in making a choice, he engages in deliberate, logical thinking. Sure, he might resolve, being sexually active is a big decision, so I’ll take my time and consider the pros and cons. I’ll talk it all over with my “partner,” and we’ll discuss STDs and contraceptives. After we make our decision, at the right time, we’ll naturally stop everything and properly put on the condom that I’ll have had the forethought to get and carry with me.
But “cool” conditions are not the real world. Place the same boy in an unexpected situation, say at an unsupervised party,64 add a cute and willing girl to the picture, along with peers who are disappearing together into bedrooms, and it’s a different story. Functional MRIs tell us that under “hot conditions”—intense, novel, and highly stimulating—he is more likely to rely on his amygdala, to be shortsighted, emotion-driven, and susceptible to coercion and peer pressure.65 In real life, his strong emotions and drives can “hijack” his ability for self-control and smart decisions.66
“The normal adolescent brain is far from mature or operating at full adult capacity. The physiological structure of the adolescent brain is similar therefore to the manifestation of mental disability within an adult brain.”54
—Daniel Weinberger, MD, NIMH
Harvard neuropsychologist Deborah Yurgelun-Todd explains, “adolescents are more prone to react with ‘gut instinct’ when they process emotions but as they mature into early adulthood, they are able to temper their instinctive ‘gut reaction’ response with rational, reasoned responses”... “Adult brains use the frontal lobe to rationalize or apply brakes to emotional responses. Adolescent brains are just beginning to develop that ability.”67
Hard science is telling us that his response to our bewildered question, what were you thinking? should not mystify us. I don’t know, the teen we love may answer, shaking his head, perhaps with tears of shame and regret. Again, most of us didn’t need Ph.D.’s to confirm what common sense told us all along—he wasn’t thinking.
It’s Not Lack of Information—It’s Lack of Judgment.
This is the case, Dr. Steinberg states, even when adolescents know and understand the risks involved.68 We can no longer assume that teens make poor choices—drug use, high-speed driving, unprotected sex—because they are uninformed or unclear about the risks. As Dr. Steinberg reiterates, “There is substantial evidence that adolescents engage in dangerous activities despite knowing and understanding the risks involved.”69
There are additional factors that make adolescence a time of increased vulnerability. With the onset of puberty, the brain is flooded with sex hormones. For many teens, this activates strong drives, excitement, and emotional intensity. It’s “a natural tinderbox,” as one neuroscientist termed the adolescent brain.71 These hormones appear to alter the levels of dopamine, a neurotransmitter involved in the reward system. The alteration produces what’s called a “reward deficiency”: 72 in order to experience the same feeling of pleasure from a given activity, whether it’s roller-coasters or rock concerts, teens require higher levels of novelty and stimulation. “It is as if they need to drive 70 miles per hour to achieve the same degree of excitement that driving 50 miles per hour had provided previously,” said Dr. Steinberg.73 Subsequently, there is an increased passion for novelty, thrills, and intensity. Add to that the sense of immortality and invulnerability that the average fifteen-year-old has, and you begin to grasp why parents of teens are nervous wrecks.
Dr. Dahl uses a powerful metaphor: an adolescent is like a fully mature car that’s turbo-charged, but its driver is unskilled, and his navigational abilities are not yet fully in place.
Professionals in other fields have responded to these findings. The American Bar Association issued an official statement in 2003 urging all state legislatures to ban the death penalty for juveniles. “For social and biological reasons,” it read, “teens have increased difficulty making mature decisions and understanding the consequences of their actions.”74 The same year, the Missouri Supreme Court overturned a juvenile death sentence, with the court referring to the volume of studies documenting the “lesser ability of teenagers to reason.” The American Psychological Association (APA) followed, with a call for psychologists to “continue to bring forth existing and new data on the limits of adolescent reasoning, judgment and decision-making.” 75
But somehow the APA—or SIECUS, Planned Parenthood, and Advocates for Youth—has yet to acknowledge that this data is relevant to sex education. They’re still insisting that deciding about sexual activity is “developmentally appropriate” for teens, that adults just need to “lay it all out there”—the risks and benefits: “Pour it all into teens’ minds and watch them process it. They can do it,” Planned Parenthood advised .76
Yet, the premise for teaching “safe sex” is based entirely on the assumption that teens can think through complex issues, plan ahead, and consider consequences. “Reasoning, judgment and decision-making,” the very things they’re still developing, are precisely the skills teens must have to determine their “readiness” for a “mature sexual relationship.” How, in light of the insights this young century has brought us about teen risk-taking and decision-making, can sex educators still tell kids, “only you know when you’re ready,” and instruct parents to “respect” their teen’s decision?
Memo to Debra Haffner, Ms. Klein, and the SIECUS and Planned Parenthood crowd: you know those “skills” you’re so keen on adults providing teens, so they can make “informed decisions”? Studying their brains has indicated: it won’t work .
You can drill it into them 24/7: you must think, talk, and plan. You can talk until you’re blue in the face: HPV, herpes, Chlamydia, and HIV; condoms, diaphragms and birth control pills; Plan B, abortion, or adoption . And you can role-play all day: communication, negotiation, and assertiveness training.
Sorry, you may have all the good intentions in the world, but even if you provide all the information, and teach all the skills, you can’t bank on producing a sexually responsible teen. The wiring isn’t finished. The circuits aren’t complete. The driver is unskilled, and only one thing will help: time.
Girls’ Bodies Are Not Ready
Girls have another underdeveloped structure that increases their vulnerability, in addition to their prefrontal cortex. The cervix, the entrance to the uterus at the end of the vagina, plays a central role in female sexual health, but few people are aware of how it increases a girl’s vulnerability to sexually transmitted infections.
The cervix is the site of two of the most common sexually transmitted infections, HPV and Chlamydia. HPV is necessary for cervical cancer to develop, and Chlamydia can cause chronic pelvic inflammatory disease, ectopic pregnancies, miscarriages, and infertility.
Girls under the age of twenty are being hit hardest77 by these epidemics. 78 One reason is their immature cervix.79
It’s critical to understand this. All things being equal,80 the cervix of an adult is more difficult to infect than the cervix of a teen. The more mature cervix is protected by twenty to thirty layers of cel
ls. In contrast, the cervix of a teen81 has a central area called the transformation zone. Here the cells are only one layer thick. The transformation zone is largest at puberty, and it slowly shrinks as the cervix matures.82 The thin folds of fragile, single cells are transformed progressively into a thick, flat shield with many layers. The “T-zone” can be seen during a routine pelvic exam. It makes the cervix look like a bull’s eye, which is fitting, because it’s exactly where the bugs want to be.
Ask any self-respecting virus or bacteria about his life goal, and he’ll tell you: to find a good home where I can be fruitful and multiply. That’s the purpose of his existence. To reach that home, the layers of cells must be penetrated. It’s difficult, if not impossible, to get through the many layers of the mature cervix.
But penetration of the transformation zone’s single layer is a cinch, making this area of the cervix prime real estate for genital infections. This is one of the reasons for our current pandemic of genital infections in teen girls.
Take note, however, that infection (the mere presence of an organism, an STI) is not enough to cause disease (an STD), which in the case of HPV, would be pre-cancerous changes.83 The body has mechanisms for eliminating the virus before it causes damage, and for fixing the damage should it occur; it has methods of preventing an infection from developing into a disease. But these strategies are impaired in an HPV-infected T-zone.
Like police forces in a city, the body has specialized units84 whose job is surveillance and safety. These are cells and organs that take care of “problems.” In the cervix, these security guards are called Langerhans cells.85 They watch out for unfamiliar “visitors.” When one is identified, it’s taken into headquarters86 for “questioning,” and taken care of—eradicated. In the T zone, compared to the more mature cervix, the number of Langerhans cells is lower,87 the security is weaker, and dangerous “visitors” like viruses and bacteria may go unnoticed. Once HPV has settled in, the virus itself can incapacitate88 Langerhans cell functioning.89, 90 So aside from having a large area that’s vulnerable to invasion, the young cervix also has a weaker “police force” to recognize and deal with the danger.
Comparison of a Mature and Immature Cervix
Also, cells in the T-zone are highly sensitive to estrogen and progesterone. 91 Studies suggest these hormones can enlarge the T-zone, empower HPV, and stimulate cervical cells to rapidly reproduce.92 That’s a hazardous combination. First, it provides bugs with more available “real estate.” Because viruses can’t replicate by themselves—they must hijack the machinery of the cell “hosting” them, their job is facilitated: hijacking is easier when the cell is working at high gear. So female hormones may boost the power of HPV to cause damage. They may also interfere with the actions of the “police force”—those Langerhans’ cells. It’s been demonstrated that taking birth control pills containing both estrogen and progesterone for eight to ten years places women at higher risk of cervical cancer. This is thought to be related to the hormones’ direct effect on T-zone vulnerability: defense is lowered and HPV power is boosted.93
The virus has other tricks up its sleeve. When new cells are made, and DNA copied, errors occur. You don’t want DNA mistakes; these are abnormal cells with cancer potential. A healthy cell has molecules that find these mistakes and repair them. HPV interferes with these molecules, allowing the damaged DNA to replicate. The abnormal cells proliferate, and a tumor begins to grow.
Amazing, isn’t it, how complex this is? I was surprised to discover, while researching this subject, a number of textbooks about just this organ, the cervix. It’s not as simple as we’re led to believe: get vaccinated, use a condom, have regular Pap tests. Following those guidelines is essential, of course, but the immature cervix is undoubtedly a critical factor in girls’ vulnerability to disease, and cannot be omitted.
There is an important caveat: Sexual intercourse speeds up the process of maturation. A study of teens who had multiple “partners” and were HIV-positive revealed that their cervixes were like those of adults—covered by many layers of cells.94 Something associated with intercourse—the mechanical insult, a substance found in semen, or the presence of an STI—speeds up the process by which the T-zone matures.95
So if a girl is having vaginal intercourse, her body “knows” it, and responds by accelerating its defense: a thicker barrier of cells. But here’s the problem. When the cells in the T-zone are proliferating rapidly, as they are after sexual debut, their replicating machinery is working overtime. As previously explained, the cell in high gear is the cell that HPV easily takes over. Since girls are likely to be infected with the virus from one of their first partners,96 this is bad news. The virus is present, and now the machinery through which it does its damage is working overtime. It is now likelier than ever that abnormal cells will get the chance to proliferate. So even though intercourse accelerates cervical maturation, a girl who has just begun having sex is more vulnerable than she was as a virgin, at least to the cancer-causing potential of HPV. This is something she should know, when she comes in for birth control or testing. The awareness of this risk, along with communication skills, may help her to begin saying “no.”
Biology Says: Wait!
How long does it take for the cervix to mature? That’s what I want to know from every gynecologist I meet. They tell me that everyone is different, but in general, as a girl moves through her teens and into early adulthood, her transformation zone decreases in size. A larger area of the cervix is covered by a thicker, tougher surface.
Now folks, this is big. Based on this finding alone—something gynecologists and pediatricians have known for at least97 twenty years, girls should be advised to delay sexual behavior. Yes, delay sexual behavior. Not for moral reasons, and not for emotional reasons (although those are significant as well, and we’ll get to that in another chapter), but for medical reasons alone.
Question: why don’t we all know about this? Why aren’t pictures of the T-zone found in every sex ed curricula, and displayed on the websites of Planned Parenthood, Teen Talk, and GoAskAlice?98 Why no pamphlet about the cervix in the waiting rooms of adolescent health providers? What happened to a teens’ right to “up-to-date, accurate medical information,” and to sex educators’ claim of providing it?
I’ve scoured the resources on this, and read all the Q&A’s from girls asking, “am I ready? How do I know?” The answer is always, “Only you can decide ....”99 Consider your values, your relationship, and how you feel about it, girls are advised. A responsible sexual relationship is consensual; honest; mutually pleasurable; protected. Always included are warnings not to have sex due to peer pressure or coercion. I didn’t find a single “expert”—who declared: you’re not ready, take it from me, it’s smart to wait and then explained the immature cervix, and pointed to it as indisputable evidence that teen sexual activity is high risk, especially for girls.
How, in 2008, do organizations like SIECUS and Planned Parenthood get away with their 1960s-era mantras about kids being “open,” questioning what they learn at home and at church, and telling them, “only-you-can-decide-when-you’re-ready,” all the while claiming to be based in science? How can they tell parents to “provide information,” back off, and respect their teen’s decision—the same teen that forgets to bring a pencil to class, and has a meltdown when her sister gets more French fries than her?
In fact, adolescent brain specialists urge the opposite approach to what sex education activists recommend. Dr. Giedd says that parents should “stick around and sort of be the highly developed frontal lobe”—meaning, be involved with the tough decisions facing your teen, even if they resist.100 Be the CEO—within reasonable limits—until theirs is fully functioning. Dr. Dahl and other neuropsychologists remind us that adolescents need social scaffolding—constraints, support, protection, and “most importantly, the rules and behaviors of the adults that provide monitoring and a ‘safety net’ for adolescents.”101 Are you hearing this? Along with our supp
ort and protection, they need our constraints and rules.
This scaffolding, they say, should come from parents, teachers, coaches and other responsible adults and should not weaken until the capacity to self regulate has emerged, and the individual is able to make increasingly independent judgments. “Adult monitoring is all too frequently and too prematurely withdrawn during this vulnerable period, leaving the adolescent to have to navigate situations alone or with peers at a relatively early age... [this] plays a part in creating a great deal of vulnerability for youth in our society.”
Amen. Teens are not small versions of adults. They need us, along with our rules and limit setting—even though they’ll rarely say so. About sex, they must be told: of course you’re interested, your urges are natural and healthy, but now is not the time. Trust us, this is not like cigarettes or fast food: one poor choice, just one, can affect the rest of your life. Be smart, we expect it of you, and we know you can do it.
Anything less than that is an awful disservice to our kids. We harm them by saying: only you know, as if, with all our wisdom and experience, we know nothing. We deprive them of the scaffolding they so need. Why then are we surprised when, like an unsupported building, they wobble and come tumbling down?
Chapter Four
A Doctor’s Oath
LIKE ALL PHYSICIANS, Ruth Jacobs took an oath when she graduated from medical school. She stood up, raised her right hand, and swore to prevent disease whenever she could. Since that day, she’s treated thousands of patients, learning the hard way that the fight against disease is sometimes lost. Early in her career, in fact, the news she gave many patients was bad; there was little to do but wait for the end. The grief of those left behind was heavy on her heart.
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