Women and people of color continue to be underrepresented in mathematics. Thus, mathematics graduate teaching assistants' (GTAs') classroom experiences are often dominated by individuals who are white and/or male. This sends a problematic message about who can access and engage with mathematics. To better understand their educational experiences, we studied a group of mathematics GTAs' reflections about short biographies from mathematicians of varying backgrounds. Analysis showed that reading such biographies provided validation for lived experiences, highlighted the lack of representation in mathematics, and shed light on ways that inequities in the education system continue to impact students of color.