EDITOR, - It has been suggested that environmental factors, possibly acting in fetal and early neonatal life, may be having long term adverse effects on the male reproductive system,1 and that this is leading to an observed deterioration in semen quality2 together with an increase in the incidence of congenital malformations of the male reproductive tract, and in the incidence of testicular cancer. Although this is currently little more than a compelling hypothesis, if true it has very profound implications for those involved in fundamental research as well as …