Novel aspects of human infertility: the role of the male factor

In the article new aspects of the 'male factor' and its role in early stages of pregnancy are described. Among others, genetic and immunogenetic (KIR/KAR, HLA) factors are underlined as well as immunological ones (e.g. microchimerism). A significant part of this review is dedicated to infectious agents and semen inflammation as well as to the TORCH syndrome and chlamydiosis, concentrating on the male part, in which there are a lot of unclarified consequences. The problem of somatic diseases and general homeostasis of the male and its influence on pregnancy with particular emphasis on previous cryptorchidism is also discussed. The role of sperm DNA integrity in the fertilization process as well as genetic polymorphisms on the male side is emphasised. Particularly, molecular aspects of HLA-G and HLA-C in developmental biology are raised. There is a discussion of the individual approach to assisted reproductive techniques, which cannot be treated as a panacea for infertility treatment, particularly considering early stages of embryonal and fetal development.