(Science) – Of all the materials valued in biomedical research, embryonic stem (ES) cells and fetal tissue have gotten disproportionate attention from politicians. Because creating ES cell lines initially requires destroying a human embryo, President George W. Bush tightly restricted the use of federal funds for research on all but a few stem cell lines. President Barack Obama then made lifting those restrictions one of his first official actions after he took office in 2009. More recently, accusations that abortion clinics were unlawfully selling fetal tissue to researchers has stoked opposition to that type of research. So far, however, members of Congress have been unable to enact any restrictions into law. Now, biomedical researchers are wondering: How will a Donald J. Trump administration handle these ethically delicate materials?