Is that an anecdotal assessment, or have you actually performed a systematic study, and if so what where the criteria?
One of the indications I had was when I was second in command, and the male boss went away for a few weeks, leaving me in charge. When he returned, I told everyone that the boss was back--and they all acted like he wasn't, and still kept coming to me for their employee issues. Some of the employees flat out told me that they preferred me over the actual boss. People outside of our division were sometimes surprised when I told them that I actually was not the boss.
He has since been transferred to another division, and I'm the actual boss now.