Research in Reproduction: Challenges, Needs, and Opportunities

After delivering a student lecture on the quantitative attributes of human infertility, the very poor quality of human sperm in comparison to other species, and the biologically unlikely long “time-topregnancy” statistics even among young people, I generally pose to my audience of several hundred young and healthy students the following question. “All of these characteristics would be enough to make most wild species go extinct; look around you; is that what is happening to us? If not, why not?” Fairly quickly, they begin to talk about medical information and research, IVF (in vitro fertilization), etc. This situation hides, however, an important paradox for those who work in or fund research in reproduction. Namely, it is one thing to look at the level of the population, and quite another to look at the individual. Many not directly involved tend to see the former level, with overpopulation an issue, and contraception mostly a socio-economic matter, and anyway infertility is not life-threatening, like cancer. For the affected individual or couple, it looks very different. Moreover, we are confronted with severe and unresolved issues in regard to livestock reproduction, as well as for endangered wildlife. In the following, selected research challenges in reproduction are listed. This is not exhaustive and less about their clinical importance, but more about the extent of our knowledge deficit and the potential translational impact such basic research could have. It will be noticeable that in many of these areas a paradigm shift in our thinking may be required. So much of current thinking about research in reproduction still relies on simplistic concepts that are at least 50 years old. The reproductive system is different from most other physiological systems in the body in that its functionality in the adult depends on a highly dynamic but very tightly controlled proliferation and differentiation of specialized cell types. And while deficits in functionality may not necessarily be life-threatening, its close informational interdependence with other physiological systems nevertheless gives it great importance in our understanding of health and disease.