In a new study, U.K. researchers administered testosterone to sixteen women (chosen over men because their baseline testosterone levels are obviously lower) and found that they were less able to intuit emotional states when shown pictures of faces. This could have applications regarding autism, which some researchers have theorized is the result of excess testosterone in pre-natal development. (Autism is characterized by an inability to read the emotional states of others.) It could also be useful for teasing your friends about their maleness, their femaleness, their compassion, or their heartlessness. Give it a try.