Under-representation is context-specific: it depends on which group is being talked about. There are still relatively few men in the HR profession and relatively few women among engineers. This is something you always need to think about if you want to find out who the members of the under-represented subgroup are in your team, department or organisation.
What really matters
What is really important are the various values and perspectives that stem from diversity. Different approaches for communicating, planning and executing tasks form the core of what is so positive about diversity. When ideas on how things should be done clash, innovation is more likely to appear – providing you manage to keep all conflicts positive.