Date: Tue, 27 Apr 1999 14:51:10 -0700 (PDT)
From: Gene Thompson <gthompso@ccsf.cc.ca.us>
To: Pinhole Listserv <pinhole@exploratorium.edu>
Subject: Re: pinhole Sister heads; Brother tails but not 50/50
In-Reply-To: <HPHHGLLHNPNBAAAA@shared1-mail.whowhere.com>
Well, let's get the biology into this discussion then.
The chances of a male vs. a female fertilization are greater, i.e. more
fertilized eggs are male, more zygotes are male, more babies born are
male. This is a balance to the fact that males have a higher death rate
than females across the board, at all ages. I think at fertilization the
rate is something like 55% males to 45% female. By birth (again, this is
all based on memory and could easily be off), it is closer to 51% male to
49% female.
Also, fertilization, it turns out, depends on the egg and the chemical
environment it creates around it as much as it depends on which sperm is
"strongest". In other words, it's beginning to look as if the sperm that
gets through is let through with the assistance of the egg.
More things to factor in when figuring chance. Aren't flipped coins
easier?
Ellen Koivisto
George Washington High School
San Francisco