The only notable impact of syphilis on Europeans, according to Crosby, was on relations between men and women. To prevent the spread of the venereal disease, European doctors began to recommend that men thoroughly wash their genitals after sexual intercourse. The most important biological development of the last millennium for Crosby is not the destructive outcome of the Columbian exchange, but the way it sparked a massive population growth in the post-Columbian era. While the indigenous population of the New World drastically decreased as a result of the exchange, for the same period the population of Europeans and Africans who arrived in the New World rapidly increased. The major cause of this development was the post-Columbian...

"The transfer of Old World plants and, especially, Old World animals," Crosby argues, "vastly enhanced America's capacity to feed [the] growing population of alien humans" (166). And later by utilizing American plants (maize, potatoes, sweet potatoes, manioc, peanuts, and beans), European, African, and Asian farmers were able to greatly improve their own capacities to supply food. In this way, the Columbian exchange resulted in a huge population growth for the entire world. Was this development then good for the world? Crosby is not certain, and ends his book with a pessimistic outlook: "The Columbian exchange has left us with a not richer but a more impoverished genetic pool. We,…