For the approximate 10 percent of readers who are left-handed:

If you are left-handed, chances are your mother was also left-handed but your father was right-handed. A woman over the age of 40 is 28 percent more likely to bear a left-handed child. A premature infant is five times more likely to be left-handed. Left-handers tend to use their right hands more frequently than right-handers use their left hands.

Experts claim that when they walk into a room, left-handers tend to turn left and right-handers turn right. Left-handers tend to be better at algebra; the reason, suggest some, is that their brains are better suited to dealing with the abstract.

Artists, musicians and academic women are more likely than average to be left-handed, but they also have an advantage as musicians because the regions of their brains that deal with sound are larger and better developed.

A larger percentage of left-handers than right-handers smoke cigarettes, which may partially explain why right-handed people live, on average, nine years longer than left-handed people.