To the Editor.— I was interested in the recent report by Smith and Steinberger (223:774, 1973) and in theLetter to the Editorby Jerome A. Silbert, M.D., (224:626, 1973) concerning the storage potential of human semen. Having been involved with the original work that Smith and Steinberger report, I can corroborate the fact that spermatozoa morility was adversely affected as time went on. However, I believe that a more important aspect of this study is urgently required. At this time we do not have definitive data concerning the possible genetic effect of freezing on human spermatozoa; it is certainly not inconceivable that some type of genetic damage may occur and may not be perceived in the gross examination of a newborn infant but might be revealed if follow-up studies were done, including psychological evaluations of the children as they mature. I wonder if this might not be the time