An electrostimulation system developed for early research with humans and the great apes, and a new constant-current stimulator specifically developed for human use, have been employed in studies with paraplegic men to produce erection and semen release by rectal probe electrostimulation (RPE). Catheter techniques for antegrade collection of the semen, uncontaminated by urine, have also been applied with moderate success. Details of the electronic instrumentation and catheter techniques are given. The procedure used with the patients and electrostimulation and semen collection results are presented.