This paper aims to empirically assess the impact of gender diversity on innovative performance, specifically research and development (R&D) in companies, in exploring the business case for gender diversity. The study's originality lies in isolating the specific effect of gender diversity on innovative performance from the effects of other forms of diversity, particularly in terms of age, nationality, status and seniority. The results show that the innovative performance of both individuals and teams would be increased by more gender balance at the team level. Another finding is that women are over-represented in some domains and on projects that are not designed to be major contributors to the performance of the activity under study, which has a measurable cost in terms of performance. Two factors of success for businesses and science are allowing more women to take an active part in core R&D and developing appropriate diversity management strategies within research teams.