Endocrine Abstracts

Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Denmark

Human birth rates are decreasing in industrial countries and are now far below levels, where our populations can be sustained. Although some socio-economic analyses suggest that the trends are due to behavioral changes, adverse health factors may also be at play. In Europe, we have epidemics of infertility resulting in increasing need for assisted reproduction. In Denmark, 9 – 10 % of all children are now born after medical assistance. Female infertility due to delays in pregnancy planning causing ’oocyte aging’ combined with partner’s poor semen quality may often be among the etiological factors. We have been focusing on possible links between increasing trends in testicular germ cell cancer and decreasing semen quality. Our work has provided evidence of a testicular dysgenesis syndrome (TDS) of fetal origin. The symptomatology of TDS includes cryptorchidism, decreased spermatogenesis, low sperm counts and risk of testicular germ cell cancer. In patients with TDS we detected a cell pattern which gives rise to testicular cancer (seminomas and non-seminomas). These precursor cells, germ cell neoplasia in situ (GCNIS), are similar to primordial germ cells of testis in first trimester (gonocytes) and express several embryonic genes, including OCT-4, in line with the theory of fetal origin of testicular cancer occurring in young adults. We hypothesize that endocrine disrupters originating from fossil fuels may play a role in the increasing trends in reproductive health problems. Perinatal exposures may be particularly harmful for normal differentiation of the embryonic gonocytes into spermatogonia in the fetal testis and thereby cause TDS, including testicular cancer in young adulthood. If the hypothesis of links between trends in male reproductive disorders and non-sustainable birth rates is confirmed, unconventional and interdisciplinary research collaborations, followed by regulatory actions, will be needed to reverse the trends.