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Question for readers to answer:

Macaque monkey,  Crab-eating macaque (Macaca fascicularis) in Lopburi, Thailand.  Photo courtesy of 'Chris huh' and Wikipedia.

If a human yawns in front of a monkey, will the monkey yawn?

Deadline:  June 4.  We will publish the best answers on June 9.

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Interacting with nature by K:

How to Offer Wild Birds Shelter in the Winter

Not all birds migrate south for the winter.  Winter is a hard season for birds, and many risk freezing to death at night. It doesn't take much effort or money to provide shelter for them, and it can make a huge difference to the little feathered guys!

More Articles >>

 

 

Choosing the sex of a baby before it is born

I have two girl babies. But I wish a boy. Can medical science help me to born a boy baby?  Saima, Lahore, Pakistan 

None of the easy procedures that we have developed to influence the sex of the new born has been proved to work, according to the rigorous standards of medical journals.  But because they haven't been proved effective, doesn't mean they don't actually help. 

If you want to try, here are some tips on how and when to have sex so it favors a boy-child, according to Dr. Shettles, who wrote a book on the subject (How to Choose the Sex of Your Baby) and researched sperm characteristics in the 1960's.

Men produce two types of sperm:  y-sperms that determine the baby will be a boy and x-sperms for a girl.  Dr. Shettles noted y-sperms are smaller (verified recently) and perhaps faster and weaker than x-sperms.  So, he recommended these practices to give the boy-producing y-sperms their greatest chance to succeed in fertilizing the egg:

  • The most important thing is timing of intercourse in the woman's monthly cycle.  Since the y-sperms are fast, have sex close to when the woman releases the ripe egg (ovulation).  Two days before ovulation through a few days after ovulation work best.  The fast y-sperms can then beat the slower x-sperms to the egg, and you end up, maybe, with a boy baby.
  • Since the y-sperms are weaker, you need to help them reach the egg by releasing them as close to the egg as possible.  Deep penetration and rear-entry (doggy style) helps.
  • The environment in the woman's womb makes a difference.  The more acid it is, the more likely it will kill the weaker y-sperms.  A woman can help make her womb less acidic by having an orgasm.

"It's difficult to put too much faith in this type of folk-lore stuff," cautions Michael Tucker, scientific director of Georgia Reproductive Specialists.  Y-bearing sperm are a little smaller and, therefore, lighter.  But whether this truly translates to being faster and weaker is "a little dubious to me!"

"This topic is obviously an ethical minefield," says Gail Sullivan, retired assistant research professor of medicine at the University of Virginia Health Science Center.  She, however, calls our attention to another "interesting (and expensive)" method of sorting x- and y-sperms by the amount of DNA the sperms carry. 

Biologist Glenn Welch operates the Beltsville high-speed sorter that separates X and Y sperm.  Photo courtesy of the USDA.

Biologist Glenn Welch operates the Beltsville high-speed sorter that separates X and Y sperm. Photo courtesy of the USDA.

The female-producing x-sperm contains more DNA than the male-producing y-sperm.  Researchers use a fluorescent dye to stain sperm in semen; the dye binds to sperm according to the amount of DNA it carries.  They shine a laser beam on the sperm, and separate the brighter glowing x-sperms from the dimmer y-sperms. 

The procedure (called MicroSort) costs about $6000, but shifts the 50:50 x- to y-sperm ratio in semen to 90% x or 75% y.  Then parents can choose the sorted semen they desire for insemination, and thereby achieve family balancing.  It's not perfect, but in the 1,000 pregnancies and 900 births so far (January 2006) 91 percent of parents who wanted girls succeeded, and 76 percent of those who wanted boys succeeded.  MicroSorting can also reduce the likelihood of having children with x-linked disease.

Further Reading

Scientific aspects of preconception gender selection, Reproductive Biomedicine Online. 10 Suppl 1:111-5, 2005 Mar.

Choosing your baby's sex FAQ

(Answered Jan. 10, 2008)

 

 
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