Designed to provide stem cells for their siblings

In a growing practice that troubles some ethicists, a Chicago laboratory helped create five healthy babies to serve as stem-cell donors for their ailing brothers and sisters.

The made-to-order infants, from different families, were screened when they were embryos to make sure they would be compatible donors. Their siblings suffered from leukemia or a rare, potentially lethal anemia.

This is the first time embryo tissue-typing has been done for common disorders like leukemia that are not inherited. The results suggest that more children than previously thought could benefit from the technology, said Dr. Anver Kuliev, a Chicago doctor who participated in the research.