http://www.nature.com/news/let-s-talk-about-sex-robots-1.22276

Enabling robots to read human behaviour and to respond in appropriate ways is a burgeoning area of research. As is the study of how humans will react to these potentially clever, personalized and ever-available companions. But there is another aspect of human–robot relationships that is rarely mentioned, and it’s one on which robots could have just as great an impact as any other. Sex.