They say that a dog will know that you are coming home before it even sees or hears you so could it be possible that they can pick up on some sort of telepathic brain wave ( I should point out that I am a believer in telepathic possibility's) ,
I use to ride a big hunt horse, the lady that owned it said that it only liked females but notice how well it got on with me , she said it was like ridding a volcano yet I was dressed basically like anyone else at the stables so not to sure if it would be a dressing thing and I think that to really find that out you would have to get your female friend to dress as a man to see if there was also a reaction from the clothing .