Sarah Eddy and her co-author Sam Long are high school and college science educators who research how to increase student motivation, interest, and retention in biology. Their work and that of their colleagues shows that teaching sex and gender more accurately in classrooms benefits not only gender-diverse students but all students and the field of science. Bills in states like Florida define sex as a binary set of biological traits. But scientists know that sex is far more complicated. For nearly two out of every 100 people, a binary definition of sex would not work. Children begin developing and testing their understanding of sex and gender starting as young as 2 years old. Erasing gender diversity even in elementary schools reinforces inaccurate conceptions of sex and gender that can last a lifetime. A 2019 study of 460 8th through 10th-grade students found that those taught an oversimplified and inaccurate definition of sex – as defined by sex chromosomes – had increased beliefs about the genetic basis of sex and in stereotypes about men and women, including unchangeable sex differences in intelligence and scientific ability. The trans and nonbinary college biology students that Sarah Eddy interviewed suggest there is another long-term harm of oversimplifying sex and gender: lack of preparation for a future career in science or medicine.