In the average human ejaculate there are several hundred million live and mobile sperm. The
older a man gets
the fewer sperm he manages to manufacture. By the age of eighty or ninety most men are
infertile, though they
often have enjoyable sex lives. In a few relatively isolated communities old men appear to sire
offspring with great
success, a facility that appears to be associated with great longevity - as, for instance, in
Georgia in the USSR
and in the valley of Vilcabamba in Ecuador. I have yet to see studies of fertility in old men in
these communities.
The oldest man I have seen quoted as still producing live sperm is mentioned by Havelock
Ellis - "the sperm
secreting function has no necessary final term and may be continued to advanced old age, even
in one reported
case to the age of 103." See "Physiology of Sex" by H. Ellis.