Sperm RNA Marks Male Fertility

Male fertility tests typically begin with measuring semen volume and the motility and overall shape of the subject’s sperm. Yet even good-looking sperm sometimes can’t get the job done. New research suggests infertility clinics may also want to assess the molecular contents of sperm to determine their fecundity, in particular the presence of 648 nucleotide sequences in sperm RNA (Sci. Transl. Med. 2015, DOI: 10.1126/scitranslmed.aab1287). A team of researchers led by Stephen A. Krawetz of Detroit’s Wayne State University found that if these RNA elements were present in sperm, then basic, relatively noninvasive fertility treatments had a good chance of achieving a live birth. Specifically, if the sperm contained all of these RNA elements, couples who had intercourse at times selected to maximize fertility or who used intrauterine insemination had a 73% chance of achieving pregnancy. The authors argue that if sperm doesn’t have all of these RNA elements, then the sperm probably cannot successfully achieve ovum penetration and fertilization, which is required in less invasive fertility treatments. It might be wiser for those couples to resort to more sophisticated and invasive techniques such as in vitro fertilization, the authors suggest.