Pete Winn | Senior Staff Writer | Tuesday, November 13, 2007
In an exclusive interview with Cybercast News Service, Gary Rose, M.D., president of the Medical Institute for Sexual Health in Austin, Tex., talked about his forthcoming book on the neurochemistry of sex. (The Medical Institute for Sexual Health describes itself as a non-profit group founded to confront the global epidemics of teen pregnancy and sexually transmitted infections.)
CNSNews.com: Your new book, in part, looks at what science shows concerning the development of the brain over time. What have you found?
Dr. Rose: For instance, we now know, through MRI studies -- magnetic resonance imaging studies that are not harmful to do -- that the pre-frontal cortex, the front part of the brain, is the last part of the brain to mature. That is the part of the brain that deals with long-term judgment and delayed gratification. By scanning multiple brains, we have shown it really is not mature until about age 25.
Guess what? As a culture, we've known that for a long time. My daughter has her master's degree but could not rent a car until she was 25. My son's car insurance rate dropped substantially at age 25. Their brains finally matured so that they could make good decisions, and it took that long for them to no longer be considered risky to car rental companies and insurance companies. We can actually demonstrate that with regard to MRI studies.
CNSNews.com: What about when people have sex?
Dr. Rose: Well, with regard to sex, we now have studies that show that when women breast-feed their babies, they secrete the hormone oxytocin, which binds them to their baby -- so that a mother is willing to do anything for that baby, even die for that baby, not because the baby is cute, but because they're bonded. We can measure that. The same thing happens when women have sex. They also secret oxytocin then, and it binds them to their partner. It chemically binds them.
Men secrete a particular hormone, vasopressin. Both men and women, when they are doing something pleasurable, secrete dopamine, which is a rewards signal -- it means, "I like this. I want to do this again." So, our drive to have sex again with this person is neurochemically driven. Our emotion has a reason. It's a neurochemical reason.
We can also show by MRI studies that intent is in different parts of the brain. So that if I give my wife a goodbye kiss and a peck on the cheek, that lights up one part of the brain, and if I give my wife a good-bye kiss, and a suggestive wink and say, "I'll be home early," another part of my brain lights up.
CNSNews.com: That's interesting, but what's the importance of that? Can you connect the dots?
Dr. Rose: This is so important because in young people their brains are still being molded. If they are getting the wrong flood of chemicals -- if their neural pathways are being developed in an abnormal way, those parts of the brain will be superhighways that can't be changed when they come into adult life.
People who have multiple sexual partners at a young age are likely going to continue to have multiple partners all their lives. Certain synapses of the brain will be pruned off -- and risk-avoidance and delayed gratification may be affected.
Here's an analogy: For people who are of Asian descent who don't already know English, if they learn it after a certain age, it's difficult for them to put the letter "L" into their words. If they learn English as children, it's no problem. It's because there's a pruning of certain synapses in the brain -- and once there is a pruning, it cannot be reconnected.
So if we expose kids to pornography, if we expose kids to overt sexuality -- and keep in mind that 70 percent of all of their music, movies, television mush has overt sexual overtones -- we are building those pathways. If we are building hypersexual pathways, and others get pruned out -- like those for sexual responsibility and modesty -- we are not going to have healthy adults.
The emotional consequences of that have not yet been looked at from a scientific perspective. But they are huge.
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