Semen comes from three main structures in the male reproductive anatomy. The first is the prostate, which forms a milky substance full of enzymes, proteins, and minerals. The second are the seminal vesicles, which produce the fructose as well as two-thirds of the fluid. The third are the testicles, which produce the sperm and some other fluid as well Did you know that if one testicle is removed, the other will grow and take over additional semen production to make up for the loss? There are literally cookbooks designed with semen in mind.