https://phys.org/news/2018-07-experts-cited-online-news-men.html

The imbalance is even greater for certain fields, such as foreign politics and business and finance, where men make up almost nine out of ten expert sources. And despite all the media campaigns and focus on equal representation in recent years, these figures haven't materially shifted since a similar study was carried out in 2010.

So what's driving this imbalance? It's true that the UK is unfortunately still a country with a well-documented under-representation of women in leadership positions across various sectors (not least news journalism), and this certainly plays a part. But previous research has identified other factors. A tendency to rely on known contacts, reliable performers and suggestions from previous informants all militate against a widening of the expert pool.