Those of us who suspect biology plays a role in explaining some group differences do not deny the existence of bias, which is especially powerful in traditional societies that lack norms of toleration and laws that protect minorities. But we are skeptical that racism or sexism or other pernicious forms of bias can explain all of the gaps that we see. More importantly, our hypothesis is falsifiable. One way to falsify it would be to find that genes which influence physical and mental traits – including abilities and interests – are identically distributed across human groups.