The message
from Roger contains these words:

ISTM that there is a widespread view that men and woman tend to have
different strengths and weaknesses. Perhaps the most widely observed of
these are that woman can multitask (talk, read and knit all at the same
time) much better than men but have a poor spatial awareness (can't
reverse a car nor navigate generally).

There are of course exceptions to these stereotypes but the One Show
(IIRC) on BBC1 a few weeks ago had an interesting take on the subject.
The argument there was that the differences are down to the level of
exposure to testosterone in the womb and the so called male and female
brains are by no means confined to their actual gender. A simple test is
apparently all it takes to establish the gender of your brain and the
test, rather bizarrely is the ratio between the lengths of your index
and ring fingers. Ring finger longer than index - male, shorter female.
The more pronounced the difference the more skewed the persons
abilities.


Very well expressed, and as you indicate, the "digit ratio" (the ratio
of the length of the ring finger to the length of the index finger) is a
very good indication of an individual who has had a high exposure to
testoterone in the critical first three months of foetal life while the
brain is developing (and in which, it so happens, relative finger
length, which is also testosterone-dependent) is also being determined.
Other things are also determined during this critical period, including
the sensitising of the skin in certain areas of the body so that it is
capable of responding to later testosterone stimulation if that should
happen to occur.

As you say, "male" and "female" brains -- and other characteristics --
don't necessarily correspond 100% to an individual's sex.

Of course, this is a piece of folk-wisdom which has been known all over
the world for many centuries. Why do you think that wedding rings are
worn on the fourth finger of, depending on the country, one hand or the
other? Because it's easy to see, looking at that hand, whether that
digit is longer than the index finger. And that in trun is a predictor
of relative fertility. A female with longer ring fingers is likely to
be less fertile becausae she is likely to have a higher
testosterone:estrogen ratio but if she does have children there is
likely to be a preponderance of boys.

As with all these things there are a lot of ifs and buts and maybes.
High testosterone in the first three months of fetal life doesn't
necessarily mean that it will be followed by high testosterone levels in
later life -- but the chances that it will are much higher than for a
female without such fetal exposure.

It's when there's high actual exposure to testosterone in later life,
from puberty onwards, that you see the difference between those who have
been sensitised by early exposure and those who haven't. High exposure
of those who haven't been sensitised in early foetal life will have
relatively little effect. Exposure to the same high levels of
testosterone of those who have been sensitised in early fetal life will
result in the development of characteristics more typical of males --
moustache growth, more body hair, restricted breast development,
deepening voice etc.

Which was really the point I was making -- even a woman (who in fact has
the longer ring fingers) with enough obvious testosterone influence on
her brain and body to produce moustache growth on a male scale and has
certainly had her brain masculinised to some extent STILL hasn't had her
brain masculinised enough to get her reasoning with regard to
thermostats etc. straight. It must require even more masculinisation to
make that reasoning a probability, so it must be a VERY male thing.