No 1, October 1990. It is usual to consider interferences with normal prenatal development from conception to birth as environmental, in contrast to a genetic intrusions which are predetermined by the time the zygote forms. In reality chromosomal and genetic anomalies are also attributable to environmental factors as for example the role of the maternal environment in the origin of cytogenetic changes and mitotic nondysjuncion after conception, which appears to be one of the first damages to the embryo caused by an adverse inner environment, which leads to chromosomal imbalances. In normal embryogenesis many genes act in an orderly sequence at certain phenocritical periods to bring about normal development. Should a specific gene fail to bring about an important and critical reaction, the whole process thereafter will be disorderly resulting in a congenital abnormality.
Many environmental agents are know to produce congenital anomalies in man.
These teratogens which are active during pregnancy include radiation, maternal disease, infections, drugs, harmful chemicals and alcohol. Foetal X-irradiation can lead to congenital malformations in man like microcephaly, skull defects, spina bifida, microphthalmia, cleft palate, micromelia, clubfoot and a host of others as reported in the literature. Presently, not only medical technologies but other sources like industrial and laboratory procedures, nuclear tests and nuclear reactor accidents have to be considered. The most dangerous of them is the high frequency x-rays or ionising radiation which has been associated with birth defects. ELF according to researchers, over long periods of time is absorbed by water in the body resulting in vibrations within the cells.