Teenage Sex Machine

The article I saw today really doesn't address sex, but it does say a lot about teens and risky behavior. But as we all know, teenagers aren't at all interested in sex.


We've all felt the surge of an adrenaline rush. It does give you a high feeling, at any age. Teenagers,it turns out, just get extra stimulated by it. University of Texas cognitive neuro-scientist Russell Poldrack says "Teenagers seek out these sorts of rewarding experiences, and this provides a little explanation for that. In the long run, it may help us understand how addictions start and develop."

The hormone in question here is dopamine. Dopamine is released in the brain as a result of an action. If the action results in a positive outcome, dopamine is released and makes you feel good. Teens, the study finds, are much more sensitive to dopamine than children and adults. The results of (successful) risky behavior are much more pleasurable to a teen than to an adult or child.

Interestingly, teenage women are not the group most likely to have an abortion. Eighteen percent of women having abortions are teenagers, while 57% of of women that end their pregnancies are in their twenties. Women aged 20 to 24 have the most abortions by age (33%) and between the age of 25 and 29, the number falls to 24%. No reason yet at as to why women in their early twenties have the most unwanted pregnancies. Perhaps researchers should cover young people from their early teens to age 25 to gauge their interest in risky actions.


Source:
http://www.guttmacher.org/pubs/fb_induced_abortion.html
http://news.discovery.com/human/teenager-brain-risky-behavior.html

Just Thinking Out Loud

Its funny, isn't it, how nature and society are at odds with each other. Nature and biology has its own agenda, and it isn't necessarily what we want. Not on the surface, anyway. Society's rules and morals try to control what nature and biology are demanding. Sigmund Freud's Id and Superego, constantly in conflict. I wonder how that is working out for us as a species and in the grand scheme of things.

Is it better to go along with Mother Nature's "plan" and accept chaos in our personal lives or should we try and control everything we do and hope we know where we are taking ourselves? Take the obesity epidemic. We thought we would have it made once we had better medicines, more (and better) food and didn't have to work as hard as our ancestors. Now we are dying of heart disease, diabetes and obesity because we are eating too much and not getting enough exercise. Those of us in the Western World are having a proverbial feast, and suffering for it. The Law of Unintended Consequences always finds a way to rear its ugly head. Order and chaos. To what degree do we prefer one over the other? To what degree do we cause one while trying to prevent it?

Take the birth control pill. Its meant to prevent unwanted pregnancies. Pure and simple. Yet some research says its changing the course of human evolution. Women like men whose immune systems are different from theirs, and the birth control pill seems to steer them towards men with similar immunity. How does this effect the next generation if we are doing the reverse of what evolution has guided us towards for generations?

The majority of abortions are done for young, unmarried women. Women under the age of 24. These are the healthiest time of a woman's reproductive lives and will produce the healthiest offspring. If evolutionary biology is correct, than many young women are getting pregnant by the most evolutionarily fit men, to produce the strongest children. This doesn't happen when the pair want it to, it happens when nature wants it to. Of course, we've found a way around that by abortion and contraception. Take that, nature!

Of course, there is the alternative: unmarried young women without two sources of income to provide for the little bundle. Teens that get pregnant usually drop out of high school or college and never go back. So much for a strong financial situation. So much for whatever ambitions they had. And what becomes of the kid? A Swedish study from 2003 found that kids raised in a one parent home are twice as likely to develop mental illness problems or addictions later in life.

So there you have it. Damned if you do, damned if you don't. I think I'll go have a vasectomy tomorrow.

http://www.cbsnews.com/stories/2003/02/04/health/main539283.shtml

Natural Selection: Survival of the Most Likely to Get Pregnant as a Teenager

If I am understanding this study correctly, its talking about how some teens have a genetic predisposition to get pregnant early. It also deals with "reproductive fitness," which isn't so much a biological quality in the teens themselves but in the number of children they have over a lifetime. A person with a high reproductive fitness quality would have more children than someone with a low reproductive quality. I should have been a biologist.

The study was published in 2001, so its a little old but it says that education level, religion and culture all play a part in determining if a teenager gets pregnant. It also shows that genetics have a say in the matter. The study repeated the fact that women with a higher level of education tender to have fewer children and have them later in life, while less educated women have more kids earlier. (That's something I've noticed. My high school pals all went to college. One of them has two kids, and that's because they were twins. A former co-worker didn't go beyond high school and she has four kids. My co-worker is 31, the youngest of my pals is 29.) University educated women had a 35% lower reproductive quality than those that left school ASAP.

Religion also played a part, with Roman Catholics have a 20% higher reproductive fitness than other religions. However, take away all of the religious, educational and social factors and genetics still have an effect. Genes seems to partly decide when a girl starts puberty, has their first baby and begins menopause. This shows Darwinian evolution in action. Women with the gene for early puberty will outnumber those that don't, giving that gene a better chance of survival.

The study was conducted by observing the birth rates of 2,710 pairs of female twins. Even after we controlled for social factors, there was still lots of genetically heritable genetic variation in the life history traits - this is a really unexpected finding," says Dr Ian Owens, a professor at Imperial College's Biology and Biochemistry Department. "Looking to the future, I would expect to pick up genetic changes within the ten generations since industrialisation."

Source:
http://news.bbc.co.uk/2/hi/health/1292228.stm

You're Much Too Young, Girl: Girls Hit Puberty at Younger Ages

Gary Puckett was ahead of his time. One of his best known songs, the 1968 classic "Young Girl," told about an older man trying to do the right thing and stay away from a much younger girl. Smart man. Over the past few years its been found that young girls are starting puberty sooner than they did a century ago, with unpleasant consequences.

There are lots of potential reason for this fact. One is the hormones put in milk. Early, or precocious puberty (I don't like that term. When I think of "precocious," I think of something adorable. Growing breasts at age 8 aint cute.) was thought in the early 1990's to be caused by an artificial bovine growth hormone called rBGH. The hormone is still in the milk and meat after it is eaten, and may have caused boys and girls (especially) to mature way too fast.

The evolutionary psychology explanation is that early puberty in girls is caused by the lack of a caring bond with her parents, particularly her father. Once again, the basic idea of evolutionary psychology is that the whole purpose of life is to pass on your genes through your children. The early puberty phenomenon is thought to be natures way of bettering the odds that a girl will get pregnant if she lives in a less than perfect environment.

Anything that may lead to a girl's premature death could possibly lead to precocious puberty. Nature is giving the girl a chance to have children before she dies. Living in a dangerous environment (such as one without a father/protector or a stable family) would possibly shorten a child's lifespan. Lack of stability could be unconsciously determined by a pre-teen girl by her mother's new husband or boyfriend. The man's pheromones would be different from her biological father's, setting her early puberty into motion.

This could be a disaster for the young woman. Those girls that grew up in stressful environments showed the following symptoms:
1. They went through puberty stages faster.
2. They had their periods about 5 months sooner than average.
3. They had sex at an earlier age.
4. They had children sooner and were less involved with them.
5. They had less stable relationships with their partners.

Sources:

http://www.livescience.com/health/070904_bad_puberty.html
http://www.psychologytoday.com/blog/the-scientific-fundamentalist/200810/why-has-the-age-puberty-declined-in-recent-decades-iii
Jones, Richard E. Human Reproductive Biology. Academic Press, 2006.