In most democracies, women are a majority in the electorate, but men are the majority of those elected. Previous studies on gender affinity voting that point to substantive, descriptive and symbolic representation are often based on polling date and focus on whether women issues were central in the election. Since electoral rules-including candidate gender quotas-impact the choices voters have, we use a novel database with precinct-level voting data for 960 candidates (397 women) in the 28 open-list proportional representation districts for the 2017 Chamber of Deputies election in Chile to identify the determinants of gender affinity voting for candidates in same party matchups and whether gender affinity voting differently impacted left and rightwing parties. Using 35,120 precincts, we analyze 1,344,098 data points for individual candidates' vote shares. We find statistically significant, but not substantive, gender affinity voting, especially favorable to women candidates in leftwing parties.