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Author Topic: Can the sex of a baby be selected?  (Read 2669 times)

Offline thedoc

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Can the sex of a baby be selected?
« on: 18/09/2012 12:30:01 »
Leslene Coulter  asked the Naked Scientists:
   Good day Chris

I absolutely love listening to you on Cape Talk Radio. I'm not sure whether I can ask you a question on this platform.

I am 33 weeks pregnant with a little girl and was just wondering whether one can naturally improve one's chances of conceiving either a girl or boy baby.

Many thanks,
Leslene

(Gorgeous) Cape Town

What do you think?
« Last Edit: 18/09/2012 12:30:01 by _system »


 

Offline chris

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Re: Can the sex of a baby be selected?
« Reply #1 on: 18/09/2012 23:14:29 »
Congratulations! Naturally you'll want to name her "Chris"!

To answer your question: there's no natural way to reliably control the sex of your offspring.

But, ignoring legal considerations, it is possible to select the sex of a baby; one way is to sort sperm into X and Y forms and then use the appropriate pool, according to the desired sex, for ivf or GIFT techniques.

The alternative is to fertilise eggs, grow them on in the dish and then extract a cell from the developing blastocyst and genotype it. Having identified an embryo of the right sex, this is then implanted into the uterus to develop.

A morally repugnant way to do it would be become pregnant naturally and then use either amniocentesis or CVS to obtain foetal tissue and genotype this, permitting only foetuses of the desired sex to continue to develop.

An even worse approach is adopted in some countries (meaning China and other parts of Asia), where there are well-documented cases of babies of the "wrong" sex (meaning usually girls) just being left to die, usually through malnutrition i.e. starving them to death. What a wonderful world we inhabit...
« Last Edit: 18/09/2012 23:18:41 by chris »
 

Offline CliffordK

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Re: Can the sex of a baby be selected?
« Reply #2 on: 19/09/2012 00:18:04 »
It is also possible to probe for the Y chromosome in a peripheral blood sample. 
I presume there are some false negatives, but a positive result would be quite accurate.

There is a concern of generating an unbalanced population with more boys than girls.  Perhaps it allows the girls to be more choosy, but it could cause hardship for some of the boys.
 

Offline chris

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Re: Can the sex of a baby be selected?
« Reply #3 on: 19/09/2012 08:09:19 »
There is already a gender disequilibrium; in Saudi Arabia and other countries where men can have multiple wives there are a lot of men left hard up (for a wife). In China, where the one child policy was relaxed if the first child was a girl, there is a similar excess of lonely men.

An interesting thing we've not touched upon though, is that girls appear to be fitter than boys; more male conceptuses are produced, in total, but fewer survive, meaning that the population sex ratio returns to 50/50.
 

Offline RD

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Re: Can the sex of a baby be selected?
« Reply #4 on: 19/09/2012 08:45:07 »
Physiological stress in the parents seems to produce a bias for daughters ...

http://blogs.discovermagazine.com/80beats/2012/03/30/natural-gender-selection-starving-women-seem-to-give-birth-to-more-daughters/


Quote
a survey appearing in the publication Scotland's Runner revealed that just 23 per cent of the children fathered by runners engaged in serious training were boys.
http://www.pponline.co.uk/encyc/0076.htm
« Last Edit: 19/09/2012 08:57:49 by RD »
 

Offline chris

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Re: Can the sex of a baby be selected?
« Reply #5 on: 19/09/2012 20:01:01 »
One wonders, RD, whether that's because the runners were too tired to "exercise" in a gentlemanly way on or just ahead of day 14, when conception of a boy is slightly more likely because the Y sperm have a slight weight advantage.
 

Offline RD

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Re: Can the sex of a baby be selected?
« Reply #6 on: 20/09/2012 05:10:06 »
Male fighter-pilots, submariners and professional scuba divers also have more daughters ...
Quote
... a recent study of submariners revealed that they have significantly more girls than boys, although researchers are not sure why.
http://news.nationalgeographic.com/news/2006/02/0202_060202_baby_boys_2.html

The physiological stress of being repeatedly exposed to sub-normal levels of oxygen could be an explanation.

So looks like any woman wishing to have a daughter should date a fighter-pilot who runs marathons,
( with the alternative option of professional scuba diver for those who like rubber outfits :) ).
« Last Edit: 20/09/2012 05:14:31 by RD »
 

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Re: Can the sex of a baby be selected?
« Reply #6 on: 20/09/2012 05:10:06 »

 

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