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AustinCBrown
03-17-2008, 03:09 AM
Hey all,

I've done a little research on the subject of gender selection, but I'm having a hard time finding conclusive answers. What I would like to know is whether or not current technology can definitively determine the sex of a child. In other words, suppose someone wanted to guarantee having a baby boy, could current science provide the person with a baby boy with 100% certainty (Assuming funds and access to the technology)? And I'm not so much interested in whether or not such science is permissable (ethically) so much as whether it can be done.

Also, could someone link me to articles or recommend literature?

Many thanks,

Austin

Mr Flibble
03-17-2008, 03:17 AM
With IVF yes, because the embryos are screened before they are implanted. If you aren't using fertility tech to get pregnant, then you have to wait and see till you can do CVS ( Chronic Villus Sampling) which can be done at 10-13 weeks gestation, but has risks attached.

basically, if you want a boy, you have to go through assisted conception to be sure.

Tsu Dho Nimh
03-17-2008, 03:27 AM
There are several currently available ways, with the safest being Ultrasound - http://www.ob-ultrasound.net/genderfaq.html and if you see a female, have an abortion. Done frequently in India, where it is illegal.

Invasive: take an amniotic fluid sample and look for chromosome material. Abort of you don't see "XY" material.

In vitro fertilization, test sex and implant only the male embryos.

TerzaRima
03-17-2008, 03:43 AM
Austin, google Microsort. Basically, it's a technique which uses a fluorescent probe to differentiate X-bearing sperm from Y-bearing sperm. The ethics is a whole 'nother story.

AustinCBrown
03-17-2008, 03:51 AM
Ok, but can they do something to the egg itself to determine the sex? Let's take implanting a male embyro into a womb out of the picture. Can current science acheive a boy by, say, manipulating the sperm itself, or doing something to an egg, or choosing a particular sperm to fertilize the egg, or whatever? Can current IVF technology acheive this directly, or do they fertilize a bunch of eggs, say, "Ah, here's one that is going to be a male" and then implant that particular egg?

Forgive my ignorance.

Austin

AustinCBrown
03-17-2008, 03:55 AM
Thanks for the link!

So far as I can determine, that increases the odds, but it still isn't a defacto guarantee... though they say they can increase the X up to 88%. Not bad, eh? But yes, the ethics is a real question, but one that I'm not addressing here.

Austin

GeorgeK
03-17-2008, 05:03 AM
...or do they fertilize a bunch of eggs, say, "Ah, here's one that is going to be a male" and then implant that particular egg?

Austin

Yes, although small there is a margin of error for everything else. Technically, there is even a finite possibility of error when you have a healthy looking baby in your arms.

Tsu Dho Nimh
03-17-2008, 07:57 PM
Ok, but can they do something to the egg itself to determine the sex? Let's take implanting a male embyro into a womb out of the picture. Can current science acheive a boy by, say, manipulating the sperm itself, or doing something to an egg, or choosing a particular sperm to fertilize the egg, or whatever? Can current IVF technology acheive this directly, or do they fertilize a bunch of eggs, say, "Ah, here's one that is going to be a male" and then implant that particular egg?

Forgive my ignorance.

Austin

The sperm manipulation techniques are used in agriculture, where you want more cows from a prize bull than the 50-50 normal split. But they only run the odds up to 75-25 or so, and that's with millions of dollars and tons of research. Hitting 90% would be heaven to them.

To get 100% with current science, you have to get an embryo or fetus to the point where you can individually test for sex: and if you don't want to do the implant of a known male embryo, you have to abort the "wrong-sex" ones.

Cranky
03-17-2008, 08:03 PM
Correct me if I'm wrong, but doesn't the sperm carry the information which determines the sex of the offspring?

I really want to know, because I keep blaming my husband for all these boy-children we have, lol!

GeorgeK
03-18-2008, 01:35 AM
Correct me if I'm wrong, but doesn't the sperm carry the information which determines the sex of the offspring?

I really want to know, because I keep blaming my husband for all these boy-children we have, lol!

In most things (including humans), yes.

Cranky
03-18-2008, 01:41 AM
In most things (including humans), yes.

Cool. So messing about with the egg won't do it, I would imagine. Thanks for answering, George. :)

Tish Davidson
03-18-2008, 06:36 AM
Speaking of normal human development here. The sex chromosome in every egg is always X The sperm carry either an X sex chromosome or a Y sex chromosome. If an X chromosome sperm fertilizes an egg, the sex chromosomes are XX and with normal development, you get a girl. If a Y sperm fertilizes the egg, you get an XY offspring who will be a boy. The man's sperm always determine the sex of the offspring.

The X chromosome is slightly heavier than the Y chromosome. If you are doing artificial insemination, you can spin the semen in a centrifuge and manipulate it so that most of the heavier X sperm sink to the bottom and the lighter Y sperm rise to the top. This increases the odds of getting the gender that you want, but it is by no means foolproof. In the normal mode of conception, you have no control over the gender of the child conceived. About 104 males are conceived for every 100 females, but more male fetuses spontaneously abort (the males are just less hardy) so that at birth the natural ration of boys to girls is 1:1.

As soon as you get a sample of the fetus's cells (they are shed into the anmiotic fluid, you don't have to take a hunk of tissue from the baby), you can look at the chromosomes and tell if the fetus is XX or XY. By exposing the fetus to certain sex hormones at critical stages of development, you may be able to get them to develop sex characteristics of the opposite gender, but this doesn't change their DNA. It is also unethical and immoral to do this intentionally, although it sometimes happens accidentally if women do not know they are pregnant and take certain drugs.

GeorgeK
03-18-2008, 06:21 PM
Speaking of normal human development here..

Right, for "normal", it's just that there seemed to be an insistence for a 100% guarantee and there are none. There are intersex patients. There have been a few famous Hollywood actress/pinup models oogled my many a man who when they went to the infertility specialists to figure out their inability to menstrate at puberty, found out that they were only phenotypically female. With regard to the amniocentesis, I know of at least one case where most likely the needle was contaminated with cells from the mother and the amnio said girl when it was a boy. He eventually grew up and fathered children so he was obviously not only a phenotypic male. I'm just making the point that there are never any guarantees at 100%.

AustinCBrown
03-18-2008, 09:19 PM
Thank you all. It was very helpful and you answered my queston. Now, time to write, and write and write...

Austin