The Cervix: Saving Some Sperm for Later

The way I see it, the female reproductive system has a love/hate relationship with sperm. It has an odd tendency to try and kill sperm one moment and protect it another. Definitely an unstable relationship.

The photos above show both sides of the love/hate aspect. The photograph at the top (borrowed from the "Beautiful Cervix Project") shows the seminal pool outside of the cervix, at the end of the vagina. This is the last place that the sperm wants to be. The vagina is acidic, even after its walls have been lubricated during sex. Sperm are sensitive little guys and acid tends to kill them pretty quickly. That's why they need to get into the cervix quickly. Its a safe haven. Not only is the cervix not acidic, its got mucus that can protect and even nourish the male's cells.

The bottom picture shows the inside of the cervix and describes how the sperm are protected. The sperm can live as little as 20 minutes outside of a human body, a few hours inside of a vagina or a week inside the uterus and cervix. That big jump in survival rates is all due to the mucus and the retaining of sperm inside the cervix.

Its important to note that cervical mucus is most helpful to sperm when the woman is fertile. At less fertile times, the mucus is actually sticky and prevents the sperm from moving. This sticky, "infertile-time" mucus keeps the sperm inside the acidic vagina. Sorry, guys. It just wasn't your time.

Sources:
http://www.amazingpregnancy.com/pregnancy-articles/250.html
http://www.beautifulcervix.com/wp-content/uploads/2009/02/cervie-post-coitus-988x1024.jpg
http://www.menstruation.com.au/periodpages/moreonmucus.html

Girls Just Wanna Have Fun

This will probably give fathers with daughters in college nightmares. Your little girl doesnt want to talk to her dad when she is in the fertile stage of her cycle. A study from the University of Miami, UCLA and Cal State (Fullerton) found that daughters are less likely to talk to male relatives during ovulation and hang up on male family members sooner than when they are not fertile.

This was found after examining the cell phone records of women aged 18 to 22 over the course of one billing period. The women were half as likely to call their dads during their fertile stage and talked to them for less time. The average length of time that a woman spoke to her father while fertile was 1.7 minutes, compared to 3.4 minutes per day while at low fertility.


There are several reasons why daughters want less male relative contact while fertile. First, they may not want to have their fathers overly examining their boyfriends. Second, they may want a distance from male family members to reduce the risk of inbreeding. The second instance seems more likely, said the researchers.

"In humans, women are only fertile for a short window of time within their menstrual cycle. Sexual decisions during this time are critical as they could lead to pregnancy and the long-term commitment of raising a child. For this reason, it makes sense that women would reduce their interactions with male genetic relatives, who are undesirable mates," said Dr Debra Lieberman, lead author of the study and an assistant professor of psychology at the University of Miami.

Previous studies have shown that many female animals avoid genetic male relatives while fertile to avoid inbreeding. Women also tend to dress more attractively and are more attracted to masculine, virile men while fertile.

Source:
http://www.physorg.com/news/2010-11-evolutionary-psychology-daughters-dont-dads.html

A Baby Boom After a Disaster? More Like a Baby Bust.

The rumors have been around for decades. After some kind of disaster, either natural or man made, nine months later there is a baby boom. While it would make sense that after a large loss of life, humanity would try to repopulate, it doesn't seem to be true.

While scientists did find that a baby boom did happen in Oklahoma after the 1995 Oklahoma City bombing, they didn't find any support for the idea that more babies are made after a blizzard. The reason for the four year increase in Okie births is that the bombing made people re-evaluate their lives and decide to have children. The urban myth that a blizzard leads to people having more sex is false because even if people were trapped by a snow storm, they would still have access to birth control.

If anything, there are fewer children born after a disaster. This was found after 9-11. Stress has a strong, negative effect on pregnancies. This was shown in the increase in miscarriages of male fetuses in September 2001. Male fetuses are believed to be sensitive to stress hormones than females. Several natural disasters have shown to create a spike in miscarriages, such as the lower than average number of male birth in Japan after the 1995 Kobe earthquake.

The researchers found that the average number of reported miscarriages for the month of September was 995. For the month of September 2001, the number increased to 1,115. "There's nothing more contagious than emotion. If something bad happens, you have a negative contagion. Having something really bad happen, it strikes me it would resonate through a population," said Dr. Sarah Berga, a professor and chairman of the department of gynecology and obstetrics at the Emory University School of Medicine.

Sources:
http://articles.cnn.com/2010-05-25/health/9.11.miscarriage.bereavement_1_fetuses-miscarriages-stress?_s=PM:HEALTH
http://www.dailyfinance.com/story/media/the-latest-blizzard-baby-boom-and-an-enduring-media-myth/19372077/

More Proof That Men and Women Are Very Different

Older women like to chase younger men, but the younger men usually prefer even younger women. Older men chase younger women and they get married.

....

Horseshit. We young guys have enough trouble finding women without them being taken by old fogies.


Its happened again. This time Hugh Hefner, an already overly lucky son of a bitch that lives with dozens of gorgeous young women that are willing to get naked, got engaged over Christmas. I wonder what the sex would be like. Its just hard to see an 84 year old having sex with a 23 year old model.

As always, science has an opinion on these situations. Unlike women, who lose their fertility around age 50, men stay fertile forever. As said in the "Survival of the Fittest: Survival of the Most Likely to Get Pregnant as a Teenager" and "Old Men, Healthy Babies" posts, there are benefits to such couplings. Teenage mothers have many more years to have more children and older fathers may have healthier sperm and be more stable parents.

There is another reason: a combination of the two. Much older men married to younger women have more children and healthier children. Researchers from the University of Turku looked through parish marriage records from the 17th through 19th centuries of three separate Sami groups in Finland. The men that married women that were on average 14.6 years younger than the men had the best "evolutionary fitness." In other words, they had the most children surviving to adulthood.

"Young Sami women were the most fertile and had the highest reproductive value, whereas older Sami men had acquired enough skills needed for successful hunting, fishing and reindeer herding and, most importantly, wealth to be good providers for the progeny and thus desirable mates," concluded Dr Samuli Helle. Still, such marriages were uncommon, with men only being slightly older than their wives. Its believed that Sami society doesn't approve of such large age differences.

Its worth noting that the age of the couples according to the parish records are likely just guesses. I've done some family tree research and the dates of birth are often in question, especially the further back in time you go.


Source:
http://www.telegraph.co.uk/science/science-news/3317353/Why-men-like-to-marry-younger-women.html

An Update and More Musings

I must have been writing for this blog for a while, because I'm noticing how one study will mirror another study in one way or another. Take the "Abortion" post. In it, I mentioned a 2007 Polish study where they claimed that voluptuous women were easier to get pregnant. I wondered if it was possible to do a study on the women (and the partner that got them pregnant) to see if they are more attractive, well endowed and healthy than the rest of the population. According to this study, that's not necessarily the case.

Last month, a study from University of North Carolina at Chapel Hill and a Norwegian team of researchers found that anorexic women are more likely to have unplanned pregnancies and abortions than women without the eating disorder. The theory behind the finding isn't so much about evolutionary biology as it is about simple misinformation. Doctors and gynecologists in the past may have told anorexic women that they stop menstruating and the women may have believed that they couldn't get pregnant as a result.

"Anorexia is not a good contraceptive,"Cynthia Bulik said. "Just because you're not menstruating, or because you're menstruating irregularly, doesn't mean you're not at risk for becoming pregnant." Bulik was the study's lead author and is the director of the school's Eating Disorders Program.

The numbers show that anorexic women are much more likely to have unplanned pregnancies. Fifty percent of women that claimed to have anorexia had unplanned pregnancies, compared to 18.9% of healthy women. Twenty four percent of anorexic women had abortions, compared to 14.6% of women without the disease.

None of this really answers the question that I repeated at the top of the page. The anorexic women may have a high degree of facial symmetry. It does show that anorexia doesn't necessarily prevent a women from getting pregnant like it was once thought. Mother Nature wants women to get pregnant, and this shows that she's more determined than we thought. This would make an interesting study to measure the difference in fertility between women of healthy and unhealthy body types.

Also, going back to the stories about introverts and women approaching college age men for sex. The statistic I provided in the introverts story said that 25% of the population has an introverted personality. Introverts tend to prefer calm, relaxing environments compared to excitement. Extroverts, on the other hand, need to be stimulated to relax.

The study on how many college men agree to sleep with with a woman that approached them for sex found that 75% of men agreed to sleep with the woman. That made me wonder if the 25% that declined the offer were introverts. It would make sense, as it would be seen by the introverted men as "too soon" to sleep with such a woman. The extroverts would have agreed right away, going by their need to be excited.

That's just my idea, I don't know if that's the case for sure. One of the first rules of science is "correlation doesn't necessarily mean causation." Meaning: just because you find that two things happen together, doesnt mean that one causes the other. Still, it does make sense from a evolutionary standpoint. Why are there so many more extroverts than introverts? Because they have more sex and more sex means a greater chance of passing on the extrovert genes. This is sexual selection in evolutionary biology at work.





Source:
http://www.heraldsun.com/view/full_story/10109746/article-Anorexic-women-more-likely-to-have-unwanted-pregnancies--abortions

I Want to Be Your Lover but You're So Shy

Am I an introvert? Oh God, let me tell you. While I'm at work, running around, cooking food for impatient customers in a noisy supermarket, the idea of sitting quietly at my computer and surfing the web sounds like Heaven. My extrovert co-workers want me to join them at the bar and take a woman home, but I don't want all of that hassle. After being in a cacophonous store for a few hours, who wants to go to a crowded, sound filled bar? Sure as hell not me. I also use words like "cacophonous."

College was a pain in the ass for me. I didn't mind the classes. In fact, I enjoyed the challenge that they gave me. "Go ahead and make all the rules for that 12 page paper, Prof. I'll still get an A." It was that damn, crazy dorm that made me feel like I was in prison. Music played as loud as possible all night long, drunks stumbling around (ok fine, I did that sometimes, too) and getting kicked out of the room cause your roomie brought some chick back gave me headaches.

Was I jealous? A little, maybe. But I genuinely preferred peace and quiet over the raucous social scene. If that meant being single, than it was a price that I was willing to pay. Still, every once in a while, a female classmate would start a conversation with me. It was never obvious flirting, which is what tripped me up several times. Women never come right out and say "Hey, wanna fuck?" They would approach with a smile and mention that my or their room mate would be gone for the weekend. Then they'd ask if I have any plans.

After I got their "code" through my thick skull, I wondered where they even got the idea to be attracted to me. Slowly, I'd figure out that they came from the classes where I spoke up the most. The classes where I kept my mouth shut? I never even got a patronizing smile out of the women in those classes. So yes, my fellow introverts, you do need to speak up. You cant avoid it. The good news is that you can do the speaking up in class, where you know what the fuck you're talking about. You don't have to do it at some party where you've never seen any of the other people before.

After you start talking with them outside of class, do a lot of listening. We're not talkers to begin with, so listening should be no problem. Look at her face, smile and nod occasionally. The trick is, you really have to be listening. They'll know if you aren't. I don't know how they know, but they know. Don't try to be Mr Funny or Mr Cool, just be genuine. If they ask for your opinion, give it but be nice.

You wont always get laid. That's just the way it is. No one ALWAYS gets laid. You win some, you lose some. But it is possible. I think a big thing that we introverts have going for us is the fact that we aren't the party animals. We're different. Women must get sick of guys that act like horny teenagers. A female co-worker (who is all of 21 years old) told me that she is tired of dating "little boys." She wants a man. I was amazed. Twenty one years old and sick to death of "boys" already.

Of course, as I said in my very first post, I'm a virgin. So yes, the title is misleading. Its not "An Introvert's Sex Story" as much as its "Yes, Women ARE Willing to Fuck An Introvert, and May Actually Seek Them Out." So if you feel cheated out of a juicy sex story, my bad. On the other hand, if I can lift a fellow introverts day by giving them hope and a plan of action, then its all worth it.

Still, this is a biology web page and this post is really short on biology. The best I can give you is that fact that introverts are made that way due to the DRD4 gene. Everyone has it, but its built shorter in introverts. It makes introverts much more sensitive to the chemical dopamine, making them want less of the activities that stimulate them. Extroverts are less sensitive to dopamine, and need the experiences to stimulate them. Hence, more talking, playing sports and having sex. More sex means more likely to get pregnant and more pregnancies by extroverted people with the short DRD4 gene means more extroverts. Three times more, apparently. Gotta say, mother nature has a winning strategy, there.

I'm not a member of the hubpages website below, but I do think that a lot of what they say is interesting. Some of it does match up with my personal experiences. Yes, its an advertisement for some seminar on how to meet people, but its still worth a read.

Source:
http://hubpages.com/hub/Why-Beautiful-Women-Love-Introverts-Like-You

The Jersey Shore: A Glimpse of the Future?

Take a good look at your great great grandchildren, everyone. A "top scientist" in 2007 claimed that humanity will one day split into two different species. Oliver Curry of the London School of Economics claims that in one thousand years, humanity will have reached its genetic peak, where people will be between 6 and 7 feet tall, live to be 120 years old and all have coffee colored skin as a result of race mixing. We will be a world of beautiful people. Men will have deep voices and larger penises, while women will have glossy hair, large eyes, hairless skin and pert breasts.

Awesome.

Then the shit goes down. Our species dependence on technology will be obvious in 100,000 years, as our immune systems weaken, we grow shorter and appear "child like." In a strange paradox, our immune systems need disease to stay healthy. Think of the immune system as being like a muscle: you need to exercise it to keep it in shape. With modern medicine doing all of the disease fighting, the immune system weakens from lack of use. After a few millenniums of modern health care, we are ironically much weaker.

Again, a grain of salt, people. The people of 50,000 years ago are still a mystery, so how can we say with any certainty what our future will be 100,000 years from now?

Source:
http://www.dailymail.co.uk/sciencetech/article-489653/Human-race-split-different-species.html

Looking to Cheat? Its in Your Genes.

Imagine what their children would be like...






















Call it a march forward in the study of human genetics or a further erosion of personal responsibility, but scientists from New York State University claim to have found a variant of a gene that causes people to be thrill seekers. Called DRD4, the gene has been found in people with adventurous personalities. The new gene is a variation of DRD4, and has been found in people with a history of cheating and promiscuity. The study found that these people were almost twice as likely to be unfaithful and when they were, they cheated with twice as many people.

Researcher Justin Garcia told Science Daily "What we found was that individuals with a certain variant of the DRD4 gene were more likely to have a history of uncommitted sex, including one-night stands and acts of infidelity." While the finding is interesting, it isn't a smoking gun for a cause for infidelity. The researchers admit that they didn't look into all possible causes that may have made individuals cheat. They went on to say that it was too early to call it "the cheating gene."

To my way of thinking, a person's biology may incline them to act a certain way but doesn't guarantee that they will. As has been noted in various posts in this blog, free will, education and religion all shape a person's actions. Biology has shown this to be true. A person with a gene for manic depression isn't guaranteed to be manic depressive. It takes the combination of genetics and environment to make a person with the illness.



Source:
http://www.torontosun.com/life/healthandfitness/2010/12/02/16404841.html