The immotile-cilia syndrome is a heterogeneous disease. The dynein arms were missing totally or almost totally, and both spermatozoa and cilia were immotile in most cases examined by us. In other cases, the ciliary axoneme displayed other defects and the spermatozoa had motility although restricted; there was no progressive motility. Fourteen men with this syndrome were all sterile. Fifteen women had the syndrome and twelve tried to become pregnant. This had been successful (one, one, and two children) in three cases only. Thus, it appears that female fertility is also impaired in this syndrome, although not completely. No case of ectopic pregnancy has been reported.