The effects induced by fusion-born neutrons within inertial confinement fusion targets are analyzed. Some of these effects, such as neutron energy deposition, are always present and play a significant role in propagating ignition. Other effects, such as the suprathermal fusion induced by knocked-on ions, are of marginal importance. The possibility of inducing internal tritium breeding and other interesting neutronic reactions is also studied, but it is found that they usually produce negligible or even negative consequences in the target performance.