In ***** if there are problems like irregularity in menstrual cycle, difficulties in oocyte production or implantation in uterus, obstacles in the oviduct, etc.
In man if there are no sperms in the semen, slow movement of sperms, or anomalies in the sperms then he becomes sterile.
But now with the help of advanced medical techniques these problems can be overcome and a childless couple can be parents.
