Why are men overrepresented in parliament, and does it make a difference? Male overrepresentation is not identical at the levels of the electorate, party membership, potential candidates, candidates and elected representatives. Contrary to the conventional wisdom of the ‘pyramid’ shape, which implies that male overrepresentation increase, the higher the level of the political system, this analysis shows that male overrepresentation is strongest at the level of potential candidates. Male overrepresentation is largest at this central, middle level of the political career ladder, and hence male representation at the various levels forms a diamond shape. This calls for analyses, first, of factors facilitating candidacy. What explains party members’ readiness to stand for election, and do these differ between men and women? Secondly, the question is whether this male overrepresentation has an impact on the policies decided by parliament? Do male and female potential candidates vary in their political opinions to the extent that it may have an impact on legislation? Data is provided by surveys among party members of nine Danish parties conducted in 2000 and 2012 on party members’ characteristics, opinions and activism.