Comment by adrian_b

Imperfect copying is only one reason for having to reject many sperm cells, and a less important one.

Meiosis, which produces both the sperm cells and the egg cells, is not a copying mechanism, unlike mitosis, which generates the other cells of a body.

Meiosis is a random generator, it randomly shuffles the DNA of the grandparents, which is stored in the father's cells, then it randomly selects half of it, producing a unique combination of genes in each sperm cell or egg cell.

The random genome generator together with the following filtering steps that will reject the bad variants, implement an optimum search algorithm for the fittest descendants.

Meiosis has greatly accelerated the evolution of the nucleated living beings (eukaryotes). Because favorable mutations are extremely rare, the probability of a living being accumulating multiple favorable mutations would have been negligible. With meiosis, if in a population 5 individuals have 1 favorable mutation each, there are good chances that soon some individuals will appear who have all 5 favorable mutations, then their descendants may become dominant and replace all others.