The situation with men is somewhat more complex. Sperm cells have a short life and are constantly being replaced from the germ cell line. If the exposure to radiation occurs within a few weeks of impregnation, genetic effects may occur. The possibility of such an occurrence reduced by the fact that a dose of 100 rems is sufficient to cause temporary subfertility or sterility. Recovery from the somatic effects occurs within 3-6 months.
Death occurs within a few weeks after exposure.
The total must not exceed 5 Rem per year. The higher limits for the extremities is based on the fact that those portions of the body do not contain significant amounts of bone marrow or other susceptible organs. For the present, all the records use the standard units of Rem or mRem. No Cell Replacement Nerve Tissue-No Cell Division 7. External vs. Internal Hazards Protection from external hazards.