1.   Another method of birth control must be used for a few months until two consecutive tests show there are no sperm left.

2.   Asian sperm is difficult to track down as well.

3.   A re-examination of the slides by other lab chemists this summer found that no sperm was present.

4.   Adrian Lister of University College London, a paleontologist who specializes in mammoths, doubts that mammoth sperm will be viable.

5.   During the trial, evidence was introduced showing that sperm was found when the victim was examined after the assault.

6.   Doctors usually make a small incision in the vas deferens, where sperm is stored, and aspirate the sperm-containing fluid.

7.   Here is the sperm.

8.   However, there are some safety concerns if sperm produced in mice were ever to be used for IVF.

9.   In Britain, the Human Fertilization and Embryology Act requires a man to give his written consent if his sperm are to be used when he is dead.

10.   It dawned on him that the sperm is already dead by the time it is carried into the egg and delivers its genes.