female:male ratio in K-3 kids

[Kimberly Anne Chapman]

On 11 Jan 1996, Jane Dorweiler wrote:

> Whether this phenomenon is widespread or not, the first thing that came to mind 
> when I heard this was the fact that it was about 6 years ago or so that I 
> started to hear theories on how to increase the likelihood of conceiving a child
> of a particular sex by controlling the frequency and/or timing of intercourse 
> relative to ovulation.  Perhaps there just happened to be many couples who were 
> trying for a particular sex child based on these methods??
> 
> Jane Dorweiler                 **  Regardless of what they say about the 
> Department of Plant Biology    **  cat, curiosity is a good thing.  It's 
> University of Minnesota        **  what makes each and every one of us
> dorwe001 at maroon.tc.umn.edu     **  a scientist!!

I'd like to have more faith in American couples and discount the 
possibility of people trying for a child of a particular sex.  That has 
some very ugly ramifications.  But I think Jane Dorweiler is definitely 
onto something regarding the frequency and time of intercourse.  We are 
all aware of the significant changes in a woman's body throughout the 
menstrual cycle.  In a genetics course I was reminded that one of these 
changes was the fluctuation of the pH of the vagina.  I was amazed to 
hear that studies have been done showing that some spermatozoa have a 
higher affinity and functioning capacity in a slightly more acidic 
environment while others do better in a more basic environment.  
Unfortunately I'm unable to recall which sperm cells are which, but I'll 
be contacting the prof who taught the course.  In light of this 
information, I would hypothesize that the timing of intercourse in 
conjunction with the current pH of the vagina is what influences which 
sperm cells live to reach the ovum, therefore having a higher probability 
to fertilize it.
	I'd be very interested in feedback.  Thanks in advance!!