Efficiency of spermatogenesis: a comparative approach.

Efficiency of spermatogenesis is the estimated number of spermatozoa produced per day per gram of testicular parenchyma. Spermatogenesis is the process of cell division and cell differentiation by which spermatozoa are produced in testes. Efficiency of spermatogenesis is influenced by species differences in the numerical density of germ cell nuclei and in the life span of these cells.

A comparative morphological study of human germ cells in vitro or in situ within seminiferous tubules.

For many infertile couples, intracytoplasmic germ cell/spermatozoon injection into unfertilized eggs may be their only hope for producing their own biological children. Thus far, success with injection of pre-spermatozoan germ cells such as round spermatids has not been as great as that of spermatozoon injection. This could be due in part to the difficulty of identifying younger (less mature) male germ cells in testicular biopsy dispersions.