WASHINGTON - Flyers in upscale doctors' offices portray it as the hot new baby-shower gift: a registry where friends and family chip in almost $2,000 to start privately banking a newborn's umbilical cord blood, just in case of future illness.

That idea of biological insurance is a long shot that most mothers-to-be can safely ignore, say new guidelines from the nation's pediatricians that urge more parents to donate their babies' cord blood - so that it might save someone's life today.

The guidelines come as the government begins setting up the first national cord-blood banking system, aiming to prevent some 12,000 deaths a year - if public banks can compete with marketing-savvy private companies that now house the bulk of the world's preserved cord blood.

Cord blood is rich in stem cells, the building blocks that produce blood - and the same stem cells that make up the bone-marrow transplants that help many people survive certain cancers and other diseases. But cord blood has some advantages: These younger stem cells are more easily transplanted into unrelated people than bone marrow is, and they can be thawed at a moment's notice, much easier than searching out a bone-marrow donor.