Methods are provided herein for conducting stimulus-response studies on iPSCs, or cells derived from iPSCs, that have been derived from perinatal cells collected from donors under null-exposome conditions. In some embodiments, multiple donors are involved. In other embodiments, the iPSCs are differentiated. The use of induced pluripotent stem cells (iPSCs) derived from cells that originate from neonates enable a scientist to largely remove the influences of age and environmental exposures, allowing a more targeted analysis of the direct interaction between a stimulus and a test subject. Furthermore, use of iPSCs derived from cells originating from multiple donors enable the scientist to obtain more precise measurements of the role of genetic differences in determining responses to a given stimulus than the use of other test materials, by eliminating the vast majority of the differential influences of age and environment among test subjects.
