The sperm and ova are alive before they unite to form a fetus. Biologically speaking then life continues and the human species survives as long  as "life continues in this manner." Meanwhile, since only one sperm is needed to join with one egg, the rest of the zillions of sperm in an ejaculate simply die even though they are each potential human life. Nature over produces sperm with other animals too  that depend on sexual reproduction like we do,to survive. That is "God's" plan. Don't forget  that part of the plan is based on animals eating other animals to survive. That is reality. Its the survival of the fittest through very cruel means, unfortunately. By the way a woman is born with about 500,000 ova. Only a fraction of those potential life units ever unite with a sperm to develop into a fetus. The rest age along as the woman does and die, unfertilized. God, nature, is wasteful on purpose to make sure the species survives. Death goes along with life.