Recruiting STEM teachers is a persisting issue that has not been fully addressed. There is little research that currently exists with regards to recruitment. While some qualitative data exists on why people choose to teach STEM as a career, there is very little quantitative evidence to support this qualitative work. In our work we draw on a large national survey study to better understand when students choose math/science teaching as a career and what predicts whether students will persist in these teaching goals by the time they begin college. Our results indicate that 76.3% of students who expressed an interest in a math/science teaching career did not continue with teaching at the beginning of college. Several factors differentiated the persisters from the non-persisters. A logistic regression model predicting persistence revealed the most important factors; the desire for money and supervising others (negative) as well as gaining knowledge between disciplines, interest in mathematics, and encouragement of middle school teachers (positive).