When Sperm Met Egg

You might think that once the screaming is done and the load has been blown, the dance of the sexes is over. The highest quality male has sown his seed in the fertile female and all thats left is nine months of waiting. While the two of you are relaxing in the afterglow, the sperm are just beginning to fight their way to the egg.

Its only about three inches from the cervix to the fallopian tubes but a lot can go wrong in those three inches. It used to be thought that sperm just swim until they bump into the egg. It turns out to be more of a challenge than that. A challenge that requires the use of senses. It turns out that sperm have a sense of touch and smell.

In 2003, Israeli scientists found that human sperm are attracted to heat and that the area surrounding an egg is 2 degrees warmer than the rest of the uterus. It also seems that sperm stop swimming on their way to the egg to fully mature. The spot that they stop is cooler than the egg. After they mature, they are ready to fertilize.

To test the theory, the scientists built a lab with rabbit sperm at one end of a tube and a heat source at the other. They found that the sperm did travel towards the 102.2 degree F area, and away from the 98.6 degree F cooler area. Even changing the temperature by one half of a degree was enough to attract sperm. However, only the mature sperm went towards the egg. The previous theory had been that chemicals produced by the egg attracted sperm. But the chemicals only worked for a short distance, while heat traveled over a longer distance.

American and German scientists came to a different conclusion in that same year. They found a chemical scent similar to that of flowers attracted sperm to an egg. They found that sperm swim fastest when exposed to aromatic aldehyde bourgeonal, an artificial compound used in commercial products to give them a flowery smell. The aromatic aldehyde bourgeonal was chosen because it was closest to the odor in the female reproductive tract. Also, a protein odor receptor though to only be in the nose was found to be in testicular tissue.

While women have been said to have a better sense of smell than men, a Swedish team found that men are better at smelling the sperm attracting chemical, bourgeonal. A study from Psychological Science found that men found women to be most pleasant smelling when the women ovulated.

Scientists say that these findings could be used to create new forms of birth control.

Sources:
http://www.psychologytoday.com/blog/sensoria/201007/olfaction-and-conception
http://www.psychologicalscience.org/media/releases/2010/miller.cfm
http://www.sciencedaily.com/releases/2003/02/030203071703.htm

Ladies: Have a Twin Brother? Are You Unmarried? Blame him.

Okay, this kind of hit home for me. No, I'm not a woman (despite what people may tell you) and I don't have a twin sibling, but my great aunt did. I did some research on my family tree and I saw that my great grandfather's twin sister never married. She had been engaged but the wedding was called off. It was one of those family mysteries that will have to go unanswered. That's what I thought.

Scientists at the University of Sheffield found in 2007 that a male fetus's testosterone can have an effect on his developing sister. Testosterone and estrogen can cross cell membrane's and pass between fetuses. Male fetuses, however, aren't as effected by their sister's estrogen, as the estrogen level of a male fetus is the same as a female's.

Dr Virpi Lummaa at the University reviewed records of a Finnish church dated between 1734 and 1888 for their data. Seven hundred and fifty four twins were born in those one hundred and fifty four years. Of the females that lived to adulthood, the women were 25% less likely to have children if they had a male twin. They were also 15% less likely to get married.

There may be several reasons for this. Testosterone may have given the females a more male personality and attitudes about child rearing. Second, testosterone may have effected the female's reproductive development, reducing her fertility.

"The study used data from humans living in a pre industrial era so as to obtain results that are not affected by advanced health care and contraception. They showed that as a consequence of a male twin´s influence on a female´s fertility, mothers who produce opposite sex twins have fewer grandchildren and hence lower evolutionary fitness," says Doctor Lummaa.

Source:
http://www.sciencedaily.com/releases/2007/06/070619104000.htm

Women Have Better Sex With Rich Men, aka I'm Going to Catch Hell for this Post

Ladies, please. Don't shoot the messenger. I'm just repeating what I read. If it makes you feel better, this study doesn't make me very happy either.

So yes, size does matter. The bigger the man's bank balance, the more orgasms a woman will have during sex. Dr Thomas Pollet, a psychologist at the Newcastle University in Britain, says “Women’s orgasm frequency increases with the income of their partner.” He and his research partner, Professor Daniel Nettle, believe that orgasms drive women to find and keep high quality partners.

The study was based off of research conducted by The Chinese Health and Family Life Survey, conducted in China. Five thousand Chinese were surveyed about income, sex and other factors. Of those five thousand, one thousand five hundred and thirty four were the basis of this study. The numbers break down this way: 121 women "always" have orgasms during sex, 408 have them "often," 762 have them "sometimes" and 243 have them rarely or never.

They cited research from the United States and Germany about the connection between facial symmetry and female orgasms, but think that the money connection is "even more important."

University of Texas psychology professor David Buss thinks that female orgasms may have many reasons. “They could promote emotional bonding with a high-quality male or they could serve as a signal that women are highly sexually satisfied, and hence unlikely to seek sex with other men,” he said. “What those orgasms are saying is ‘I'm extremely loyal, so you should invest in me and my children’."

Blogger's Opinion: I'm not a professional scientist but I minored in psychology at Illinois State University. One of the things they made clear is that "correlation doesn't always mean causation." Just because two things may be linked to each other, doesn't mean that one causes the other. I would want to have more details on these couples before I can agree that money makes women into orgasm machines. And I'm not just saying that because I make $17,000 a year.

Source:
http://www.timesonline.co.uk/tol/news/science/article5537017.ece