Complex sentence: Dr. Crusher explains to the Aldeans that their shield has weakened the ozone layer of the planet, exposing the inhabitants to ultraviolet radiation, leaving them unable to bear children and would likely have the same effects on the children from the "Enterprise".
Split into simpler sentences: Dr. Crusher explains to the Aldeans that their shield has weakened the ozone layer of their planet, exposing the inhabitants to ultraviolet radiation which has left them unable to bear children. The radiation would likely have the same effects on the children from the "Enterprise".