Answer:
genetic traits and diseases can be inherited from one generation to the next and therefore it is clinically relivent. if this is not enough, there are phenomenia that allow for selection of these heritable traits (e.g. natural selection as well sexual selection) that can effect animal populations, and arguably modern human populations too.
perhapse a less convicing argument for the general public and organisations that fund research, but its a phenomenea we don not understand. furthering our understanding of the world around us, can be seen as a desirable thing, and the study of it (through genetics, ebryogenesis and epigentics to name but three feilds) can lead to some interesting and important conclusions. for example, the study of epigentic inheritence has lead to much more successful and directed research on cancer.