REDWOOD CITY, Calif., Feb.

At present, when a woman undergoes preimplantation genetic screening (PGS) in a fertility clinic, doctors are trying to select an egg or an embryo that is healthy and doesn't have a chromosome abnormality such as an extra copy of chromosome 21, which causes Down's syndrome.

Although clubfoot is one of the most common congenital birth defects, few genetic causes have been found.

In largest study to date, chromosomal microarray analysis picks up more abnormalities than current tests.

Mice who inherit a particular chromosomal duplication from their fathers show many behaviors associated with human autism, researchers report in the June 26th issue of the journal Cell, a Cell Press Publication.