Infertility is an increasing problem for both individuals and societies. The number of couples seeking treatment for infertility is increasing each year, and public interest seems to be rising along with the new treatment methods and the improving results. Male infertility is also of great interest now that several studies suggest a deterioration in the quality of semen in many countries, Finland being an exception. The assisted reproductive technologies have improved tremendously since the first child conceived by in vitro fertilization was born in 1978. The new techniques include e.g. intrauterine insemination (IUI), gamete intrafallopian transfer (GIFT), in vitro fertilization (IVF), intracellular sperm injection (ICSI) and various combination treatments. These treatments are costly and both physically and emotionally stressful, and the success rate varies according to the aetiology of infertility, the age of the woman treated and the method used. More information is needed about the aetiology and incidence of fertility disorders as well as about the availability of treatment in the circumpolar areas and the couples' opinions of treatment. Our own study population, which was drawn form the northern Finland birth cohort for 1966, provides an outstanding opportunity to study these issues, since data are available for the whole life course of the individuals, dating back to prenatal life.