Striking differences between physics and biology have important implications for interdisciplinary science, technology, engineering, and mathematics (STEM) education. The author is a physicist with interdisciplinary connections. The research group in which he works, the Center for Nonlinear Dynamics at the University of Texas at Austin, is converting into the physics department home for biological physics. Many of his collaborations have been with faculty in engineering. For the past 15 years, he has been codirector of the program at the University of Texas at Austin that prepares secondary science and mathematics teachers (UTeach, 2012). The future teachers take a course on scientific research he developed and deliver together with colleagues from biology, astronomy, chemistry, and biochemistry (Marder, 2011). This background naturally makes him an enthusiastic advocate of interdisciplinary education at the secondary and undergraduate levels. Yet at the same time, the author is worried by some features of what may be coming. These worries have to do with what can happen as educators are all lumped together under the heading of STEM.