From: Kylie 31/01/2000 16:14:00
Subject: Influencing the gender of a child post id: 32873
A friend of mine recently raised a question for which no one present could answer. Nevertheless everyone was interested in whether there might be a scientific explanation/response to the question. Thus, the reason for this email.

The question is:

"Can a couple hoping to have children influence the gender of a child."

In other words there are many stories, what I would call "myths", about methods you can employ to ensure that a child is either male or female. We were wondering whether there are any proven methods that can be effectively employed to increase the probability of having either a girl or a boy.

I look forward to receiving your thoughts on this topic.
From: helen 31/01/2000 16:23:00
Subject: re: Influencing the gender of a child post id: 32876

I'm not sure you could consider it a "proven method", but temperature may have an effect. Apparently more boys are conceived during summer, more girls when it's cold.... at least in Germany :-).
From: Zardoz ®
Subject: re: Influencing the gender of a child

From
http://news.bbc.co.uk/1/hi/sci/tech/400451.stm"
Boys like it hot

Study is based on meteorological and birth data

When soaring summer temperatures put the thermometer in the pink, more baby boys are conceived, a German scientist says.

And when winter's chill sinks the mercury into the blue, more baby girls are conceived. Alexander Lerchl of the University of Münster has discovered that more boys are born in Germany between April and June, and significantly fewer in October.

Experiments with rats and bats had already hinted that environmental temperatures could affect the sex ratio of offspring, says New Scientist magazine which reports on the unusual study.
Dr Lerchl searched German meteorological and birth records over a 49-year period from 1946 to 1995. He found that sex ratio seemed to correlate with temperature about one month before conception.

Effect on testes
Hot summers or unseasonably warm patches during this period yielded more boys, while unusually cold weather favoured girls. Temperature deviations of just a few degrees centigrade appeared to have an impact.

One explanation, says Dr Lerchl, is that temperature affects processes within the testes. He speculates that hot spells may damage sperm carrying an X chromosome more than sperm carrying a Y, so more boys are conceived.

He also speculates that the temperature rise that global warming may bring could further increase the ratio of males to females, which already favours boys by a few per cent. However, there could be a more prosaic explanation for the effect - people have sex more often when it is hot.

Frequent sex increases a woman's chance of conceiving as soon as she ovulates.
Other studies have shown that this results in more sons, possibly because sperm carrying a Y chromosome are faster but less robust than X carriers which stand a better chance if they have to wait for ovulation.




From: Elke 31/01/2000 16:40:00
Subject: re: Influencing the gender of a child post id: 32883
There is a very old method used for influencing gender, however, my scientific explanation may not be accurate, and my only references are word of mouth. Males produce different types of sperm (in 1 ejaculation) in order to ensure "survival of the fittest". Some sperm specifically kill off any sperm already present, some sperm act as lubricant for other sperm, some sperm race quickly toward the ovum (but dont live for very long) and some sperm go slowly (but have longer lives). It is believed that the sperm with the y chromosome ( future males) are the fast swimmers with the short lives, while sperm with the x chromosome ( future females) are slow swimmers but have the longer lives.

Based on this, if copulation takes place during ovulation, the y-chromosome carriers will reach the egg first (therefore producing as boy). If copulation takes place a day or two before ovulation the fast swimmers will have died and the slower swimmers will be left to fertilise the egg (producing females).
From: Cal 31/01/2000 16:53:00
Subject: re: Influencing the gender of a child post id: 32888
There is no scientific basis for any of the theories to determine the gender of a child. The sperm is simply an 'outer casing' for the chromosomes it carries and there is no reason to believe that a sperm carrying an X chromosome will behave any differently to one carrying a Y.
From: Dr. Ed G (Avatar) 31/01/2000 21:59:00
Subject: re: Influencing the gender of a child post id: 33027
You can increase the chance of having a girl I believe by putting the sperm in a centrifuge and extracting the heaviest sperm for insemination, but it's not 100 percent and you can't do the converse in order to increase the chances of a boy.

Soupie twist,
Ed G.

From: Kothos 31/01/2000 22:07:00
Subject: re: Influencing the gender of a child post id: 33035
you can't do the converse in order to increase the chances of a boy.

Dr Ed, why?

If you extract the heavier sperm and use of it increases the likelihood of having a girl, shouldn't the use of the sperm that isn't extracted (the lighter sperm) increase the chances of having a boy?

Unless the rule is, 'heavy sperm create girls, light sperm create either boys or girls'. But if all sperm taken together has a 50% chance of creating either gender, surely the culling of female-creating sperm should leave at least some bias to male-creating sperm in the remaining part of the sample?
From: Rapunzel 31/01/2000 22:21:00
Subject: re: Influencing the gender of a child post id: 33047

"Can a couple hoping to have children influence the gender of a child."

Elke's point was good, but obviously intercourse on the day of ovulation is no guarantee for a boy, it just somewhat increases the chances of one - similarly, last intercourse 2-3 days preceding ovulation somewhat increases the chances for a girl; for the reasons outlined by Elke, and possibly temperature reasons as well. I was reading a book on the Billings method which had references to some studies that had been done on this subject, but a friend of mine has permanently borrowed the book!

Another comment in the book was that acidity tended to favour X-chromosome bearing sperm.

.

From: Dr. Ed G (Avatar) 31/01/2000 23:51:00
Subject: re: Influencing the gender of a child post id: 33138
Unfortunately I don't have a reference to hand (sorry, and in the absence of such supporting evidence you are quite justified to discount anything I say) but the rational for this as I recall was that "female" sperm by virtue of their carrying an X sex chromosome are heavier than "male" sperm which carrying a Y sex chromosome. Again, this is only a recollection from something I read last year sometime, so it could be wrong, although I fairly certain that current technology only allows you to increase the chances of getting a girl, not a boy.



From: Dr Dr Ian S 12/02/2000 0:43:00
Subject: re: Influencing the gender of a child post id: 37587
Rapunzel is correct. The Billing's Method works in 'much more than 50% of cases' especially when trying to conceive a girl.........Your temperature should be taken first thing in the morning and graphed over at least two cycles.....at the time of ovulation your temp rises by about one degree. If you stop fucking around about 2 days prior to ovulation most of the smaller and weaker Y sperm cells die days leaving some Xs to achieve nirvana i.e. produce a girl............My wife and I used this method to conceive a daughter.
As well, we own a horse stud and use a similar system to achieve a high percentage of fillies!
Good luck,
Dr Ian

This forum is un-moderated. The views and opinions expressed are those of the individual poster and not the ABC. The ABC reserves the right to remove offensive or inappropriate messages.