2 Sexes of Nematode Worms (IMAGE) University of Utah Caption The larger worm in the top image is a hermaphrodite -- a worm with male and female organs -- while the worm on the bottom is male. Biologists at the Brain Institute at the University of Utah genetically manipulated the brains of hermaphrodite worms so they were attracted to other worms of the same sex. The study showed sexual orientation is wired in the worms' brains. Credit Jamie White, University of Utah Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.