Microsurgical Epididymal Sperm Aspiration (MESA) is performed when there is a blockage to sperm flow that cannot be corrected. Having one of the world’s largest experiences in this procedure, I extract sperm from outside the testis, freeze it at one of the many IVF groups I work with, and they use it later as a source of sperm for a cycle of ICSI. The pregnancy rate is excellent. I authored the first papers on intentionally freezing the sperm, now a commonly used approach in the top IVF centers.