Identical Twins

YesterdayTrack: Sergei Bubka made a shocking exit when he failed to make even one successful pole vault. And Jackie Joyner-Kersee couldn't keep up with Germany's Heike Drechsler in the long jump, settling for a bronze. And Derartu Tulu won the 10,000 meters -- the first track gold by a black African woman.Tennis: Jennifer Capriati beat Steffi Graf to capture the Olympic gold and pronounced the whole experience "cool." And Germans Boris Becker and Michael Stich, both struggling this year in singles, won the doubles title.

Strong new evidence supporting the emerging consensus that many cases of schizophrenia are caused by a virus or other trauma that strikes the fetus during the second trimester of pregnancy was reported yesterday by an Arkansas neurologist.A growing number of neurologists now are confident that schizophrenia, which affects as many as 2.5 million Americans, is caused by congenital abnormalities in the areas of the brain that control thought and perception. But it has not been clear whether those abnormalities were inherited or caused by something in the environment.

SCRUBBED UP AND SLICKED down for a holiday photo, many brothers and sisters look alike. But you don't have to be a parent to know that looks are deceiving; when it comes to personalities, passions and talents, siblings can be as different as a mixed pod of sweet and black-eyed peas.Why is that? You might guess inborn predilections, and you would be partly right: Each brother and sister gets a different mix of genes from Mom and Dad, so it makes sense that whatever power nature wields over personality traits such as optimism or anxiousness shapes each sibling a little differently.