Male/Female Sperm

[MRaverz]

I've heard claims that there are differences between androsperm and gynosperm, that being sperm containing a Y chromosome and that containing an X chromosome. Specifically that the androsperm is faster, but weaker than gynosperm.

There also seem to be a number of companies which sell 'kits' which help you determine when is the best time to have sex in order to have a girl/boy based on this.

In two days worth of research, I've only managed to find an extract where it is claimed to be a hypothesis but no actual studies regarding this.


Does anybody have any idea whether there is any substance to this claim and, even better, does anybody have access to any peer-reviewed papers regarding the issue?

 

[Master_Ghost_Knight]

Well theoreticaly the Y chromosome is lighter than the X. However observation indicates that such factor hapears to make no difference what so ever.
On a side note, even if the bastards have to swim there isn't much discerning factor when you drop the load, the bastards on "front of the race" may even miss the target altogheter while the "retarded one" (that can't even swim straight, the bastard) gets there. My prediction is, this will epicaly fail because the researcher is thinking to linearly, however I can be wrong.

 

[Story]

When I saw "Female Sperm" I let of a childish chuckle thinking that the person who made this thread hadn't been taught about the birds and the bees yet. At least not in depth...

But yes, this is interesting, because I've also heard about the Chinese Conception Chart, which tells you what age and month you're likely to conceive a certain gender and it matches up with the birth dates of my siblings (I have 17). My girlfriend wants us to follow it... to have a girl (she's obviously sexist)... But to be honest I'm not interested enough to research and disprove it.

 

[MRaverz]

When I saw "Female Sperm" I let of a childish chuckle thinking that the person who made this thread hadn't been taught about the birds and the bees yet. At least not in depth...

But yes, this is interesting, because I've also heard about the Chinese Conception Chart, which tells you what age and month you're likely to conceive a certain gender and it matches up with the birth dates of my siblings (I have 17). My girlfriend wants us to follow it... to have a girl (she's obviously sexist)... But to be honest I'm not interested enough to research and disprove it.

I could change it to Androsperm and Gynosperm if you really want? :lol:

Well theoreticaly the Y chromosome is lighter than the X. However observation indicates that such factor hapears to make no difference what so ever.
On a side note, even if the bastards have to swim there isn't much discerning factor when you drop the load, the bastards on "front of the race" may even miss the target altogheter while the "retarded one" (that can't even swim straight, the bastard) gets there. My prediction is, this will epicaly fail because the researcher is thinking to linearly, however I can be wrong.

I had suspected the same thing, but I need more than suspicions.

 

[Master_Ghost_Knight]

I had suspected the same thing, but I need more than suspicions.

I am not a biologist so that is all you are going to get.

 

[MRaverz]

I had suspected the same thing, but I need more than suspicions.

I am not a biologist so that is all you are going to get.

Thank you any way.

You did well to confirm my suspicions, now I know I'm not crazy.

 

[Aught3]

Does anybody have any idea whether there is any substance to this claim and, even better, does anybody have access to any peer-reviewed papers regarding the issue?

Nope, nothing doing in the world of peer-reviewed science. I did find one paper that said the two sperm types were indistinguishable on the basis of size and shape, but nothing on speed.

While it is true that the X chromosome is bigger than the Y it doesn't seem like this would have a huge impact of speed and longevity. The sperm also has to carry 22 other chromosomes, several mitochondria, and a rather large tail. I should think the effect of an X chromosome would be pretty negligible compared to other variations in structure.

 

[MRaverz]

Does anybody have any idea whether there is any substance to this claim and, even better, does anybody have access to any peer-reviewed papers regarding the issue?

Nope, nothing doing in the world of peer-reviewed science. I did find one paper that said the two sperm types were indistinguishable on the basis of size and shape, but nothing on speed.

While it is true that the X chromosome is bigger than the Y it doesn't seem like this would have a huge impact of speed and longevity. The sperm also has to carry 22 other chromosomes, several mitochondria, and a rather large tail. I should think the effect of an X chromosome would be pretty negligible compared to other variations in structure.

I think I'll take this to my lecturers next week, I tried emailing PZ Myers - but no reply.

 

[Giliell]

The web seems to be fullk of the myth and empty of science.
Here's the best I could find:

Timing intercourse for gender selection is based upon the belief that X-bearing sperm live longer than Y-bearing sperm and that Y-bearing sperm swim faster than X-bearing sperm. However, studies which have attempted to correlate the sex of offspring with timing of intercourse have reported conflicting results. There is no strong evidence that timing plays an influential role in gender selection.

Personally, I'd say that any study that looks at factors that determine the sex would be highly difficult to conduct. Most people don't talk to their doc about getting pregnant before they are if there are no problems, which means that if you have a sample group where you could check the factors in advance would already be a non-representative group.

The problem with the boy/girl time of cyclus-story is that you usually don't know when ovulation actually happens. There's a window, but since that hypothesis depends on the exact time, it's hard to meassure. So a woman might think that it is the earliest possible time for conception and therefore a girl would be more likely, when in reality, ovulation is already taking place.
That's why, for the sake of practicality, the age of a pregnancy is counted from the first day of her last period, because the time of conception is unknown. Doctors will try to adjust the date with ultrasound, but largely don't bother to do so.

Oh, and from personal experience: I took all the sperm I could get. Resulted in two great girls.
So here's my hypothesis: Have great sex with a great partner whne time's right and you'll have great kids. Fuck fairy-tales and ideas about the right sex of your child. If you have a healthy child and complain about the sex being wrong, you don't deserve a child at all.


Edit: Sauce: http://www.uscfertility.org/blog/post/196-gender-selection

 

[monitoradiation]

Oh, and from personal experience: I took all the sperm I could get. Resulted in two great girls.
So here's my hypothesis: Have great sex with a great partner whne time's right and you'll have great kids. Fuck fairy-tales and ideas about the right sex of your child. If you have a healthy child and complain about the sex being wrong, you don't deserve a child at all.

I had a great chuckle reading that, thank you :3

 

[biology4life]

This all rang a bell.

I have a memory of some research showing that fathers absent for long periods e.g soilders, salors, offshoreworkers having more offspring of one gender, can't remember which way round.

However a quick trawl of the google machine turns up nowt so it migth be just a load of bollocks.

 

[nasher168]

I'd have thought that a group of animals in which the female sperm swim slower would be doomed to gradual extinction. If you had too many of one sex, you'd get a similar situation to some areas of China (with more males than females) and the population would slowly be replaced by other, more balanced groups.

 

[Anachronous Rex]

I'd have thought that a group of animals in which the female sperm swim slower would be doomed to gradual extinction. If you had too many of one sex, you'd get a similar situation to some areas of China (with more males than females) and the population would slowly be replaced by other, more balanced groups.

Mind you, I have no idea if this is true or not, but I believe the explanation goes:

The Y chromosome is more vulnerable then the X chromosome (which is true, as Y has lost the ability to repair itself using its opposite, a trait which all other chromosomes possess), therefore while the X-sperm are slower, the Y-sperm are more likely to die, and male embryos as well, so it evens out.

 

[MRaverz]

The web seems to be fullk of the myth and empty of science.
Here's the best I could find:

Timing intercourse for gender selection is based upon the belief that X-bearing sperm live longer than Y-bearing sperm and that Y-bearing sperm swim faster than X-bearing sperm. However, studies which have attempted to correlate the sex of offspring with timing of intercourse have reported conflicting results. There is no strong evidence that timing plays an influential role in gender selection.

Personally, I'd say that any study that looks at factors that determine the sex would be highly difficult to conduct. Most people don't talk to their doc about getting pregnant before they are if there are no problems, which means that if you have a sample group where you could check the factors in advance would already be a non-representative group.

The problem with the boy/girl time of cyclus-story is that you usually don't know when ovulation actually happens. There's a window, but since that hypothesis depends on the exact time, it's hard to meassure. So a woman might think that it is the earliest possible time for conception and therefore a girl would be more likely, when in reality, ovulation is already taking place.
That's why, for the sake of practicality, the age of a pregnancy is counted from the first day of her last period, because the time of conception is unknown. Doctors will try to adjust the date with ultrasound, but largely don't bother to do so.

Oh, and from personal experience: I took all the sperm I could get. Resulted in two great girls.
So here's my hypothesis: Have great sex with a great partner whne time's right and you'll have great kids. Fuck fairy-tales and ideas about the right sex of your child. If you have a healthy child and complain about the sex being wrong, you don't deserve a child at all.


Edit: Sauce: http://www.uscfertility.org/blog/post/196-gender-selection

Awesome reply. It all seems to be stacking up against the differences in sperms then, at least for any major significant difference. I'd guess that this is a case where someone believes something in the hope that they'll get a boy/girl out of it. Then 50% of the time, they think it works and the other 50% of the time, they assume they did something wrong.

Commenting on your hypothesis though, you seem to infer that I'm trying for a certain sex of child. If so, don't worry - kids are years ahead of me yet, lol. :lol:

@nasher: The rates would even out as one sex has an advantage being quicker and the other survives for longer. Plus, there are slightly more boys in the world anyway. 51% boys, I think.

 

[Giliell]

@Nasher
No, the (colloquial sense) theory is that while the Y-sperms are faster, they're also less likely to finish the race if the target is far away. So if you have sex at the beginning of the fertile days, you're more likely to have a girl, but if you have sex when the fertile days come to an end, you're more likely to have a boy.
Problem is that the fertile days are not that easy to know, which is why "natural" family-planning is so unreliable and still the .modern types where you meassure certain hormones in the urine are not as reliable as other contraception.

@MRaverz
Ehm no, I'm not infering anything. It was more some kind of generic advice to whomever it may concern :lol:
BTW, the link I posted also presents the different real sciency methods to tell X from Y. They're still only working on increasing the odds unless you do genetic tests as part of IVF

 

[Doc.]

Various in vitro techniques have been developed in an attempt to separate X and Y sperms using:1) differential swimming abilities of the two types of sperm, 2) different speeds of migration in an electric field, and 3) microscopic differences in the X and Y sperms. The use of selected sperm sample in artificial insemination may produce a desired sex. Others claim that timing and management of sexual intercourse can enable a couple to choose the sex of their child, A study of 3.668 births, for example, found that the proportion of male births was higher when sexual intercourse occurred two or more days after ovulation than when it occurred at or near ovulation; however, no method of controlling the human embryo's sex as been shown to change the sex ration consistently.

from textbook of embryology

 

[PatrickTheScienceGuy]

TBH there is little way to naturally force a girl or boy, its basically chance.