Astronauts on a trip to Mars would be exposed to very high levels of radiation which can cause serious long-term health problems such as cancer and sterility. Radiation shielding can help, but it is extremely heavy, and the longer the mission, the more shielding is needed. A better way to reduce radiation exposure is to simply get where you are going quicker.
Hmm. So putting them in a ship with a giant nuclear fission reactor is safer?
I think somebody may want to come up with a backup plan…
https://www.space.com/nuclear-powered-rockets-to-explore-solar-system.html
