This actually a great question. I believe that there are couple of reasons. Firstly, it is the fact that women are underrepresent in majority of industries, particularly in the dimensions of compensation and career trajectory. In turn, this estops the professional and financial success of talented women, which is why they aren't able to get far enough to become an angel investor. Secondly, there aren't enough female role models. Apart from known investors (Barbara Corcoran and Lori Garnier on Shark tank), women with a lot of potential for success don't have role models, which is why they also don't have a good reason to even go as far as becoming angel investors. Lastly is the idea risk aversion. Research in behavioral finance has proven that women are significantly more risk averse than men. Because most new businesses are almost always risky at their earlier stages, this may create a barrier for women investors from becoming angel investors due to element of excess risk.