Belarus citizens have soaring levels of infertility and other serious health problems 14 years after the Chernobyl disaster, doctors announced yesterday. One quarter of Belarus, a country downwind from the Chernobyl site in the Ukraine, was subjected to severe contamination from the accident. Within seven years of the disaster, mortality rates were outstripping birth rates, said Vladislav Ostapenko, head of Belarus’s radiation medicine institute. Girls in contaminated areas had five times the normal rate of deformations in their reproductive systems, boys had three times the normal rate, and some 2,500 babies were born each year with genetic abnormalities. Thousands of cases of thyroid cancer, which is normally rare, have been recorded in areas with high radiation levels. Ostapenko said Belarus needs more outside help to cope with what he calls a “demographic catastrophe.”