Preeclampsia still ranks as one of obstetrics major problems. Clinicians typically encounter preeclampsia as maternal disease with variable degrees of fetal involvement. More and more the unique immunogenetic maternalpaternal relationship is appreciated, and as such also the specific ‘genetic conflict’ that is characteristic of haemochorial placentation. From that perspective preeclampsia can also been seen as a disease of an individual couple with primarily maternal and fetal manifestations. Factors that are unique to a specific couple would include the length and type of sexual relationship, the maternal (decidual natural killer cells) acceptation of the invading cytotrophoblast (paternal HLA-C), and seminal levels of transforming growth factor-β and probably other cytokines. The magnitude of the maternal response would be determined by factors including a maternal set of genes determining her characteristic inflammatory responsiveness, age, quality of her endothelium, obesity / insulin resistance and probably a whole series of susceptibility genes amongst which the thrombophilias received a lot of attention in recent years.