The comprehensive epidemiological study on SIDS appears in this week's issue of Britain's THE LANCET.

The study was done by Robert Carpenter of the London School of Hygiene and Tropical Medicine and colleagues to verify earlier suggestions that when two or three unexpected unexplained infant deaths occur within a family they are more likely to be unnatural than natural.

"Our data suggest that second deaths are not rare and that the majority, 80 to 90 percent, are natural," Carpenter said.

He said for a number of reasons including the need to protect parents from false accusations, it is essential all sudden unexpected infant deaths are submitted to a detailed, expert investigation like his study, which includes a full family history, clinical history, and pediatric autopsy.