It's the number one killer of women in the U.S. and UK, and yet heart disease is sometimes thought of as a man's disease. The American Heart Association warns that women's underrepresentation and research for cardiovascular disease is putting lives at risk and is calling for greater focus on women's health. But as Emma Keeling discovers, it's not just heart disease where gender bias is a problem. There is a historical bias across the medical profession that continues to persist today with life-threatening consequences.