Diversity in teams

Just saw an interesting talk regarding diversity in teams https://www.youtube.com/watch?v=lPtPG2lAmm4 the study shows e.g. that with at least 20% women in a team innovation increases. Yet, only 30% of German top companies have at least one woman in their board. Someone needs to inform them that about 50% of the population is female. How difficult can this be? This is 2018 after all!