Final answer:
Following a vasectomy, men still emit semen without sperm during ejaculation, as the procedure blocks sperm transport, leading to sperm being reabsorbed by the body over time, resulting in infertility.
Step-by-step explanation:
Men who undergo a vasectomy procedure still emit semen when they ejaculate because the procedure involves the removal of a small section of the vas deferens (or ductus deferens), which prevents the transport of sperm from the epididymis to the urethra. The testes continue to produce sperm, but without the vas deferens to transport them, the sperm are reabsorbed by the body over time. Thus, during ejaculation, the semen does not contain sperm, rendering the man infertile.
During ejaculation, sperm normally exit the tail of the epididymis and travel through the vas deferens. Post-vasectomy, though the semen is still ejaculated, it no longer contains sperm, making fertilization impossible. The remaining sperm in the system, which are no longer able to exit the body due to the vasectomy, are kept in the epididymis where they eventually deteriorate and get reabsorbed by the body.