The American Astronaut plot
"Space is a lonely town."
Samuel Curtis is a space traveler from Earth who deals in rare commodities. At one point he gets his hands on a cloning device with the ability to create a Real Live Girl. He travels to the all-male planet Jupiter (where women have always been a mystery) to trade the Real Live Girl for The Boy Who Actually Saw A Woman's Breast. He then wants to deliver The Boy to Venus, the planet where only women live. His nemesis Professor Heiss has since tracked him down, so Curtis and The Boy have to go into hiding from the professor, who kills everyone in his path. Except for the one with whom he still has business to deal with...