Drysdale emphasized that sexual intercourse should be pleasurable for both sexes, but believed that the ever-present possibility of pregnancy prevented it from being so. He also believed that overpopulation itself was a major cause of poverty for which birth control was a solution. He also believed that fear of having more children encouraged men to turn to prostitutes, and was also a strong inhibitor of a women's willingness to express their sexuality. Drysdale also believed that immoderate amounts of sexual activity were dangerous, and he was horrified by variant sexuality, including masturbation. In spite of the limitations of Drysdale's ideas, Havelock Ellis was greatly influenced to enter the field of sex research by reading Drysdale's book.

Only six pages of Drysdale's book were devoted to contraception. He discussed five techniques, two of which, the sponge and the douche, he advised were to be used together. His douche solution, however, was simply tepid water, which he held would flush out the sperm from the vagina, after which the sponge could be removed. He also advocated that women use a safe period, which he said was from two to three days before menstruation to eight days after  Coitus interruptus, he wrote, was “physically injurious” because it might cause mental disorders and illness in the man and it also interfered with pleasure.The condom, in his mind, was unaesthetic, dulled enjoyment, and might even produce impotence. Digital facsimile from the National Library of Australia at this link.