Sex in in outer space could be deadly, according to a new study from the University of Montreal.

Researchers studying the reproductive processes of plant cells found that gravitational changes could compromise the development of human offspring conceived during space travel, The Daily Mail reported. Scientists believe that cell behavior evolved under the force of Earth’s gravity. …

“Intracellular transport processes are particularly sensitive to disturbance, with dramatic consequences for cell functioning,” said Montreal University biologist Dr. Anja Geitmann, the study’s lead scientist.