God of Sperm tells the remarkable story of Dr. Cappy Miles Rothman, the son of notorious gangster Norman "Roughhouse" Rothman, who went on to become a trailblazer in the field of reproductive medicine.

Rothman started the California Cryobank, one of the world's largest repositories of reproductive genetic material and cord-blood stem cells. Among other achievements, Rothman also pioneered the use of microsurgery in urological procedures, postmortem sperm retrieval techniques, and was one of the first practitioners of andrology, a specialty dealing with male reproductive biology and medicine.

How Cappy Rothman went from Mafia scion and man-about-town during the postwar Miami Beach–Havana era of gangster chic to one of the most consequential figures in modern medicine is an epic, only-in-America tale and also a fine reminder of the broad horizons and wild possibilities life in the US can offer.