Family History and Offspring
Does a family's history in any way determine the chances
of a child being born male or female? Lets a family has 4 boys and 1 girl
is it more likely that thier kids will be boys?
For most people there is a 50% chance of having a boy or girl. That is, no
matter how many children a couple may have had, each time there is a 50% chance
of the child being a boy and 50% chance of a child being a girl. However,
there are ways to favor the sex of a child based upon where the egg is in its
migration down the fallopian tubes. Genetically speaking, some males have
mutations in their own DNA which causes survival of sperm carrying the XY
chromosomes or the YY chromosomes. Additionally, there are situations when
there is a sex-linked diseases which cause the fetus of one sex to abort.
Probability says that each child born has a 50% chance of being born boy or
girl. But we all know families where there are all boys or all girls. I
have read that there is some kind of effect due to the biochemistry of the
male and the female and how the sperm and egg react together though. For
example, sometimes the pH of the vaginal canal can be higher or lower and the
sperm can be more or less motile and the way the two mix together can be more
conducive to males or females being conceived. I don't really think there is
any test for this however, so I don't know about the predictability of this.
K. Van Hoeck
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Update: June 2012