A pathologist or any licensed physician, osteopathic physician, or surgeon may conduct a postmortem examination when written consent thereto is given by whoever of the following assumes custody of the body for purposes of burial: father, mother, husband, wife, reciprocal beneficiary, child, guardian, next of kin, or, in the absence of any of the foregoing, a friend or person, including a governmental agency, charged by law with the responsibility for the burial. If two or more persons assume custody of the body, the consent of one of them is sufficient. The consent shall include the consent to the retention by the pathologist or licensed physician, osteopathic physician, or surgeon who conducts the postmortem examination of tissues, including fetal material, of the body removed at the time of the postmortem examination to be used for necessary or advisable scientific investigation, including research, teaching, and therapeutic purposes.