Why is the Age of Bar/Bat Mitzvah Gendered?

While almost all Jewish communities celebrate a boy's Bar Mitzvah at 13, many communities are split for girls—some 12, some 13. Why should girls be required to do mitzvot before boys? What does this age split accomplish? And is it still relevant in egalitarian Jewish communities?Have a question you'd like answered on Responsa Radio? Email us at [email protected]