"The most irrefutable finding is our demonstration that a father’s age is a major risk factor for schizophrenia."
The title is a quote from Dr. Dolores Malaspina
Poor, rural roots
Cho's parents have always struggled to make ends meet.
Sung-tae Cho, the killer's father, came from a poor rural area. He was a "country bumpkin" and considerably older than his wife, the daughter of a refugee, said Seung-hui Cho's great-aunt, Kim Yang-soon. "We practically forced her to get married."
Hyang-im's father had fled south during the Korean War that separated the south from its communist northern neighbor, according to Korean news reports.
Sung-tae and Hyang-im Cho were ambitious and apparently educated because after they settled on the still semi-rural outskirts of Seoul, they bought a used-book store. One could make a decent living selling secondhand books in the 1970s, before South Korea's economy began to boom. But one relative said the bookstore just eked out a profit.
To ease his family's plight, Sung-tae Cho left his wife behind to be a laborer in the Middle East, working on oil fields and construction sites in Saudi Arabia for most of the 1980s.
Back home, his wife gave birth March 22, 1982, to their daughter, Sun-kyung. On Jan. 18, 1984, Seung-hui was born.
For the first few years of Seung-hui Cho's life, the family lived in a dark, damp basement apartment on a busy commercial street in Shinchang, a suburb of Seoul. They lived at the bottom of a three-story, red-brick home, and paid $150 a month, a bargain even then.
Cho attended an elementary school a short walk from his home. About 950 students attend today, about half the number when Cho was there. The cluster of three-story buildings frames a large, U-shaped dirt courtyard.
The school files contain only a single sheet of paper on Cho, showing he left the school in August 1992, at age 8, after partially completing second grade.
"We don't know anything about that student," said the vice principal, who refused to identify himself. "And I'd like to point out that he did not graduate from here."