I hope I didn't sound too abrasive in my last voice card. For some reason, I find this topic strangely compelling. Also, I was (and still am) somewhat riled up by a book I read recently by Dr. Joyce Brothers.

The book is all about the differences between men and women and although it is full of truly interesting statistics, the good doctor also engages in some very sloppy thinking and smugly passes on her own opinions as established facts. One of her chief complaints about men is that they don't spend nearly as much money on psychologists as women do; Dr. Brothers feels this is clearly some kind of macho nonsense that must be nipped in the bud and she urges her female readers to drive their men into therapy as soon as possible.

So I guess I'm still fuming at her. Sorry 'bout that. My real purpose in writing this card is to share some interesting results that appeared in the November 26 issue of Science News.

Researchers have shown that adult women tend to excel at some skills and do worse at others during certain phases of their menstrual cycles and that they are simply better than men at certain things - and vice versa.

When a woman experiences low estrogen levels, she excels at tasks involving spatial relationships but performs poorly at complex motor tasks. High estrogen levels have the reverse effect. But even at their best women perform spatial tasks less well than do most men at their worst, and even at their worst perform fine motor skills and speech articulation better than do men at their best.

Estrogen seems to enhance function of the brain's left hemisphere and may also preferentially activate the frontal portions of the brain. In addition to affecting daily functioning, sex hormones also help shape brain development in the womb and thus lead to differences in male-female brain circuitry.

Several caveats: men have hormonal cycles just as women do and researchers expect to find the same kind of fluctuations in men. Also, individuals can vary widely from the norms and in any case, biological differences "often fade under the bright light of societal bias."