Why are there more male leaders, both corporate and political, than female? A new study has confirmed something we have all long suspected - a fair bit of gender bias.

The study from the Pew Research Center, and reported by McClatchy Washington Bureau, found that when it comes to strong leadership, most people rate the genders equally. According to the survey of 1000 men and 1000 women, almost 70% said they thought gender was irrelevant to the question of whether a person could be a strong leader.

But drill down further and it's a different story.Only 6% of respondents said women make better leaders, compared to 21% who believe men do.

The most interesting part here is that the results were consistent across both the men and women surveyed. And that suggests there is some deep seated gender-based assumptions embedded within many people's ideas of what makes a good leader.

Until that changes, we can expect women business and political leaders to be an anomaly.