1.   Chronic myelogenous leukemia, or CML, is characterized by an excessive growth of white blood cells caused by a chromosomal defect that produces a damaging enzyme.

2.   Most miscarriages are caused by chromosomal defects, but other factors include uterine deformities, infections and illnesses.

3.   The problems included abnormalities of the heart, kidneys and urogential system, as well as chromosomal defects.

4.   Zev Rosenwaks, a reproductive endocrinologist at the Cornell Medical Center in New York, is trying to understand the cause of serious chromosomal defects.