Performing Together: Monozygotic Twin Comedians/Twin research: Mirror-Image Cleft Lip and Palate; Dental Caries; Noninvasive Prenatal testing; Capgras Syndrome with Folie à Deux/In the News: Athletic Twins; Transgendered Twins; Crib-Sharing; Common Careers.

Twin studies have shown that our sense of humor has an underlying genetic component, but less investigation of the origins of stand-up comedy has been undertaken. This article briefly reviews twin research findings on humor, then describes the working partnership and social affiliation of a pair of monozygotic male twins who perform together as stand-up comedians. The abilities, personalities and temperaments of these twins suggest future avenues for research in this interesting area. Next, findings from twin studies and case reports of twins with cleft lip and palate, dental caries, noninvasive prenatal testing and Capgras syndrome (with folie à deux) are summarized. In conclusion, recent news about athletic twins, transgendered twins, crib-sharing and career choice are presented.