February 22nd, 2011, 02:20 PM #1
What are the REAL differences between X sperm and Y sperm??
Conventional wisdom claims that X sperm and Y sperm are very different critters. Sure, they split from the same cells and matured in the exact same environment for 90 days prior to ejaculation, but somehow according to some of these theories, the second they leave a man's body, they begin to behave in dramatically different ways. Let's take these one at a time and see what the science has to say.
1) X and Y sperm are different sizes and shapes. MOSTLY FALSE - It is true that X sperm are ever-so slightly bigger than Y sperm, because they carry 2.8% more genetic material (that tiny little arm of the X chromosome that is not present on the Y) and as a result their heads may be as much as 1% wider across or no different at all depending on the individual sperm. (sperm come in a variety of sizes). To put in perspective of how very small a difference that is, each sperm has 22 full sized chromosomes and then the 23rd which is either an X or a Y - the size difference is just that one tiny arm of the X. Everything else is the same between the X and Y sperm. (there's a good picture here http://en.wikipedia.org/wiki/Karyotype - half of those chromosomes pictured are in X sperm along with the slightly bigger X chromosome, and the other half are present in Y sperm along with the slightly smaller Y chromosome). Not much of a difference.
Researchers have investigated this idea extensively in a series of studies and most have found no difference between the size and shape of X and Y sperm - not head length, not width, not area, tail length, or in any size or shape. And they checked this in both men with normal sperm and unhealthy sperm and found the exact same thing - NO discernible difference in size or shape (aside from the very small 2.8% difference in genetic material, of course)
Here is one study that did seem to prove there were some subtle differences and that X sperm do seem to have a 1% larger head radius than Y do, but on balance, most researchers have not been able to find major differences between X and Y sperm.
UPDATE!! A new study using highly advanced technology was able to differentiate between X and Y sperm using several variables having to do with size and shape. But please understand that these differences are SO microscopic that it still debunks the idea that X are big and slow, Y are small and fast. The researchers could not tell X and Y apart using size, shape, etc - it was only by combining ALL those things together and using the most cutting edge technology, that they were able to differentiate between X and Y. What this study is really saying is that X and Y are so similar in every regard that they are virtually indistinguishable and I believe this puts the "X big, Y small" to bed for once and for all. http://www.plosone.org/article/info%...l.pone.0059387
Where did this idea come from? Our old friend Dr. Landrum Shettles, who over 40 years ago looked at sperm through a microscope and noticed that there were some with fat heads and some with pointy heads and after trying to count chromosomes in them and giving up, jumped to a rather large, if understandable conclusion, that the fat heads were X and the pointy heads Y.
However, a good deal of much more advanced technology has been invented since then and researchers have since found that what Shettles believed were X and Y sperm, were in fact uncapacitated and capacitated sperm - sperm have to lose their round ends in order to fertilize an egg and undergo a process called "capacitation" after ejaculation.
There is NO way that anyone can look through a microscope and tell which sperm are X and which are Y. In fact, research on sperm is made very complicated by the fact that in order to observe sperm by basis of genetics, you have to alter them by using fluorescent dyes that may alter their actual characteristics. Keep that in the back of your mind whenever you read anything about sperm and how they behave, because a lot of researchers have been studying sperm that wasn't counted in advance of studying them (so who even knows what the percentages of X and Y sperm were there to begin with), weren't counted accurately after experimenting on them, and/or may have been altered in some way by the process of observing them.
2)X and Y sperm swim at different speeds - FALSE. Once Shettles decided that big and round = X and small and pointy = Y, he was off to the races. He decided that ~if~ X and Y were drastically different in size, that meant that X sperm were slow and Y sperm were fast and that is why he came up with his timing method. That's right, the ONLY reason anyone ever thought that timing intercourse mattered in gender ratio at all was because of one man's mistake.
Now Shettles could be ever so slightly right, Y are just a wee bit smaller. But as anyone who has ever watched the Olympics knows, athletes come in many sizes and shapes and just because an athlete is 1% larger than another athlete, does not mean that he/she will be 1% slower. Size can bring with it advantages as well as disadvantages.
Also, research indicates that while sperm do swim, the cervical mucus has currents in it that actually help move the sperm around to where it needs to go and that these currents may actually do more to bring the sperm to the egg than the motion of the sperm itself rendering any theoretical difference in speed largely meaningless anyway. In fact, some of the fastest-swimming sperm are dead on arrival and incapable of fertilizing an egg!! Given that 140-160 males are conceived for every 100 females, if Y sperm really were significantly faster than X, this is not what you would expect to see if Y sperm were really superfast and superfast sperm are incapable of fertilizing an egg.
3) X sperm are strong and live a long time and Y sperm are weak and susceptible to damage - FALSE. Again, Shettles, believing that the uncapacitated sperm were X sperm, assumed that since these "X" sperm were bigger, they were also stronger and hardier than Y sperm. Since this was all based on his misinterpretation of what he viewed, this idea is also completely false. Both timing and pH theory rely heavily on this completely disproven idea.
In fact, research suggests that Y sperm may actually survive longer than X sperm in vitro. http://onlinelibrary.wiley.com/doi/1...1.00427.x/full
That having been said, X and Y sperm ~may~ capacitate at different rates and theoretically this could have something to do with gender ratio. It doesn't seem beyond the realm of possibility that timing intercourse or pH could play some part in this process. http://www.medical-hypotheses.com/ar...251-9/abstract http://journals.cambridge.org/action...ine&aid=183247
4) X and Y sperm swim differently - TRUE. When observed in vitro, X and Y sperm do seem to swim differently, even though they swim at the same speed. (IN COWS.) But it is not known how that translates to in vivo (in your body) conditions. Also, the numbers of sperm onhand seemed to affect how the sperm swam.
pH is often suggested as having something to do with this process but in the study below, pH is not mentioned.
MOST of the action that moves sperm to the egg has nothing to do with the sperm itself. Muscle contractions, cilia lining your Fallopian tubes, and the movement of cervical mucus throughout your reproductive tract are all much more efficient ways of moving sperm than how the sperm swim anyway.
(Continued below - there is a whole very important second part to this essay that is down a couple of posts beneath this one.)
Last edited by atomic sagebrush; August 24th, 2013 at 10:26 AM.
February 24th, 2011, 01:49 PM #2
PART TWO -
5) X and Y sperm "like" different pH levels - UNKNOWN BUT DOUBTFUL This is another idea straight from Dr. Shettles. He surmised that if X were bigger and Y were smaller, then X would therefore be stronger and Y would be weaker. Thus, an acidic environment would kill off mostly the Y sperm and the X would stay behind to fertilize the egg. He suggested douching with vinegar to aid in conceiving a girl and baking soda for a boy. Many, many people have expanded upon this idea over the last 40 years and run with it and you can buy various preparations that are supposed to help you conceive your desired gender. In fact, patents exist for some of these products and are often presented as "scientific evidence" that pH affects X and Y sperm differently. A PATENT IS NOT SCIENTIFIC EVIDENCE. In fact, a patent can prevent other independent researchers from testing the product/method to see if it even works.
Most of the at-home high tech methods you read about online such as "modified swim up", "swim up" and "the turkey baster method TBM" are variations on this theme as well. These are based primarily around the research of Dr. Ronald Ericsson. http://en.wikipedia.org/wiki/Ericsson_method http://www.in-gender.com/Gender-Sele.../Ericsson.aspx Dr. Ericsson's spinning technique is based partially around pH, partially around the idea that X and Y sperm swim at different speeds, along with spinning sperm (using the supposed larger weight of X sperm to separate them out). The Ericsson method uses different solutions to encourage sperm of different genders to swim to certain levels in a test tube and from there they can be weeded out and used to impregnate people. Problem is, there are TONS of studies that refute Ericsson - Ericsson himself is pretty much the only person who's ever gotten his method to work reliably (aside from the many licensed clinics bearing his name, of course) and if highly trained researchers in multimillion dolllar labs can't do it, it seems very unlikely that people at home armed with toy centrifuges can.
Further casting doubt on Ericsson's claims, after all this spinning and separating sperm, the ratio of sperm left behind is STILL 50-50. Ericsson admits this but claims that despite this seeming contradiction, the sperm in question goes onto conceive children in the proper gender ratios 70-80% of the time. IF this is true, that still doesn't prove that pH has anything to do with it.
Anyway, returning to the matter at hand, pH - if Dr. Shettles was wrong to begin with, then WHY would pH really matter that much? (not saying it doesn't, just pointing out that the entire idea of pH is based on a flawed premise and incorrect information). ~If~ X sperm and Y sperm are pretty much the same size and swim pretty much the same speed and live pretty much the same time and are pretty much equally hearty, HOW does pH matter?
Corollary to this question is an observation that I have made - in the vast majority of people without serious medical issues, semen and EWCM (at ovulation) are both slightly alkaline (in the 7's) and sperm goes from semen to EWCM and then swims through it to fertilize the egg. Yet most couples manage to conceive children of both genders without requiring baking soda or Crystal Light. WHY would God/Mother Nature require pH any different than what is normally there, in order to conceive a baby of a certain gender? WHY would low pH = girls and high pH = boys if medium pH is best for ALL sperm to survive in? It doesn't add up to me.
6)X and Y sperm have different electrical charges. FALSE. Originally, in the late 80's/early 90's, some researchers believed they had discovered a difference in electrical charge between X and Y sperm. Some even went so far as to suggest that the egg alters its charge to attract different gender sperm depending on several different variables. However, these studies were later invalidated, firstly because the method the researchers had used to differentiate between X and Y sperm was fount to be inaccurate (VanKooij and VanOost 1992 I cannot find this actual study online but it is widely cited). http://www.springerlink.com/content/w148x71v8762r2wn/ (I don't even understand this study but it is widely cited as debunking the electrical charge idea) http://www.ucm.es/info/genetvet/pred..._DNA_pools.pdf and http://jas.fass.org/cgi/reprint/38/3/603.pdf also debunk the idea that electrical charge is different between X and Y sperm.
The existence of Microsort itself is evidence against the "electrical charge" idea. The way Microsort works is, sperm are colored with a fluorescent dye and forced through a flow cytometer one at a time. They are encased with a tiny drop of liquid that has an electric charge and then separated out using an electrostatic deflection. IF different-gendered sperm had these charges to begin with, why would Microsort simply not separate them with electrostatic deflection? Answer - because they can't, because it doesn't work.
Some companies are more than happy to take your money to do this, but the reason why none in the United States do it is because IT DOESN'T WORK and the FDA does not license products that don't work. http://www.choicebabyconcept.com/choicemethod/lab.html
7) X and Y sperm "like" different amounts of electrolytes (calcium and magnesium for girls, sodium and potassium for boys)in cervical mucus because of their electrical charges, and these electrolytes are what attract them to the egg. FALSE. If X and Y sperm don't differ in their electrical charge (see number 6 above) then there is NOTHING supporting this idea. This doesn't mean that there is nothing to the idea that changes in diet can alter the gender ratio because that idea actually has a lot of scientific support. But it's almost certainly NOT because your egg is charged a certain way or cervical mucus is filled with positive or negative ions due to the amount of electrolytes in your diet.
8)X and Y sperm have other, different surface properties and these when combined with chemicals present in semen and CM may alter gender ratio in some way. PLAUSIBLE BUT UNKNOWN. http://www.bioscirep.cn/bsr/011/0265/0110265.pdf seemed to find two populations of (unsorted) sperm that had different surface properties and hope was raised that these two populations would later be found to be X and Y sperm. However, in a follow-up study done two years later by the same researchers, http://onlinelibrary.wiley.com/doi/1...40313/abstract it was later found that these were actually two different groups of Y sperm that were carrying different antigens.
Other subsequent studies that looked for differences in surface proteins and antigens that were presorted for gender prior to study, all failed to find any differences (I won't cite all these because there are a lot of them and they are not really helpful but here are a couple http://www.ncbi.nlm.nih.gov/pubmed/8916045 and http://www.ncbi.nlm.nih.gov/pubmed/9306971). A major problem with presorting sperm prior to studying them is, it is VERY likely that any differences in surface qualities are altered by the flow cytometry used to sort the sperm. Some other very small peptides such as the H-Y antigen (previously found on sperm with mixed results in terms of gender ratio) are so tiny that they are very difficult to detect. That does not mean that the differences are not there, just that they are very hard to find.
In an outstanding metanalysis, http://www.uky.edu/Ag/AnimalSciences...rence/dc19.pdf researchers Melissa MacFarlane, Angela Maschiari, and Richard Pursley explain why they believe differences in the cell surface of X and Y sperm do not exist and will never be found and I totally agree with their logic. To paraphrase: Sperm are formed from one cell that divides into two (please see my essay http://genderdreaming.com/forum/show...-X-AND-Y-SPERM!!! for more about this process). As sperm divides from one XY cell into X sperm and Y sperm, the X and Y stay connected for some time while the genes swap genetic info between the set of genes that are going to end up in the X sperm and the genes that are going to end up in the Y sperm. In a process known as crossing over, some of the genes your husband inherited from his mother trade places with some of the genes he inherited from his father, ensuring that both sons and daughters will inherit a diverse amount of genetic info from both their paternal grandparents. The cells do not divide until AFTER all this genetic transcription has taken place, X and Y sperm are really just one big megasperm wearing the exact same skin, until after all this swapping has occured. They are really the same cell until all this happens, and then and only then do they divide into two. This seems to indicate that whatever is on the outside of both sperm is basically the same.
It is certainly possible that there could be some mechanism that kicks in after the sperm are separated but there is no evidence to support this.
NUTSHELL VERSION - X sperm are very slightly larger than Y sperm but appear the same in most other ways. X and Y sperm have been observed to swim slightly differently in a test tube. Most of the supposed differences between X and Y sperm are based solely on the mistaken ideas of a well-meaning and actually quite brilliant man who was completely wrong and has been proven wrong beyond a shadow of a doubt.
Last edited by atomic sagebrush; June 15th, 2012 at 01:40 PM.
February 24th, 2011, 04:24 PM #3
Great piece of info Atomic, thank you.Mummy to 3 beautiful girls
for a brother for my girls
February 24th, 2011, 06:54 PM #4
wow thank you!and my HT
March 26th, 2011, 09:27 AM #5
Do you still want that article, atomic? I've got it.2005, swayed for boy, arrived 25/11/2011
March 26th, 2011, 09:45 AM #6
Yes! I would LOVE to have it.
March 27th, 2011, 03:55 AM #7
HA, managed it. Didn't realise I had to go advanced. Here you go!2005, swayed for boy, arrived 25/11/2011
March 30th, 2011, 09:19 AM #8
Thank you so very much Freya! I see I missed a post there (sometimes I am oblivious LOL!!) Thanks again.
May 3rd, 2011, 12:39 PM #9
I just find this great info! I hate shettles BTW...
But I feel so down now.
it's like no matter what we do just don't matter it's not going to change anything.
We just can't do nothing to get pregnant with a gender we want to.
And for some reason some of us only get girl or only boys.
So wth Im doing here swaying anyway?
May 6th, 2011, 03:15 PM #10
Don't get down, just because we don't totally understand how it works yet and got a few things wrong, it doesn't mean that it doesn't. We don't need to know how gravity works to not fly off the planet LOL.
No matter what, we do know that some things do seem to sway because the gender ratio does seem to vary in unexpected ways - it's not just 50-50 for everyone.
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