For centuries people had been forced to rely on less than reliable methods, such as early withdrawal of the troops before the invasion could commence, carefully tracking the rhythm of a woman's cycle, prolonging breastfeeding to the point that the baby could ask for a suck, and women shoving various mixtures of gobbedy-gook up their vaginas (of which the Professor's favorite is the Ancient Egyptian's use of crocodile shit). However, that all changed in the 19th century thanks to the invention of devices like the condom, diaphragm, and sponges. Thanks to consistently reliable birth control, the fertility rate in the United States dropped by 50 percent between 1800 and 1900. For the first time people could bump uglies without worrying about babies, transforming sex from the occasional risky endeavor to a recreational past time and setting the stage for the growing women's rights movement. Of course the conservative smut smashers of the day couldn't let such a travesty stand. In 1873 the restrictive Comstock Laws were passed, which amongst other things made it illegal to send contraceptives through the mail. This was followed by various states, counties, and even cities creating their own laws to limit contraceptives. With such restrictions in place, things of course got weird.
In 1889 a German scientist, whose name is not important, invented a disinfectant to help fight the spread of cholera, a wonderful shitting yourself to death disease that we really don't worry that much about today thanks to anti-biotics and cities not dumping raw sewage in the same places they get their water. The disinfectant proved to be pretty good at wiping out germs and soon after became available to the public at large as the cleaning product Lysol. Now this was all well and good, but unfortunately soon after various women got it into their heads that any product that could kill germs could also probably kill sperm. As a result, hundreds of thousands of women across the country began douching with Lysol, which is exactly as horrible as it sounds. Imagine squirting a caustic chemical up your nether regions. Does it sound fun? Fuck no, but that's what these women were doing. The use of Lysol in such a fashion resulted in burning, inflammation, and in a few cases even death. However, such discomfort was considered worth it if someone could avoid an unwanted pregnancy.
Now of course eventually news of this travesty reached the ears of the company that manufactured Lysol. Being a socially responsible company they of course attempted to dissuade the use of their product in such a fashion. No wait, scratch that, the ass hats actually began advertising their product specifically as a spermicidal douche. By the early 1930's, despite being illegal, condoms and other non-burn the shit out of one's vagina products were widely available. However, Lysol was the number one form of contraception used in the U.S., mostly thanks to it's relatively cheap price and the fact it didn't involve putting thick raincoats on dicks. This was rather interesting given that research from the time showed that Lysol was only effective 50 percent of the time, which seems pretty low given the side effects, but hell, who are we to question what our great grandparents did with their genitals?
Now one might think that the makers of Lysol would be content being the number one contraceptive in the country, but that my friend only means you don't understand how marketing works. In order to further branch out their product, an advertising campaign was launched to convince women that they not only needed to douche to stop unwanted babies, but also because their vaginas were super smelly. I know that the good Professor can at times exaggerate things a bit, but this is not one of those times. The ads literally told women that their husbands didn't love them anymore because of their lady stank.
This mad mad world continued throughout the 1940's and 1950's despite countless doctors advising their patients to stop squirting toxic chemicals up their hoo-haws. A decline in market share and growing concerns over certain chemicals eventually led Lysol being re-formulated and marketed instead as a bathroom cleaner. However, despite this many women continued to use it even into the 1960's. The final death knell for Lysol as a contraceptive was the one-two punch of the birth control pill being invented in 1960 and the Supreme Court ruling that it was unconstitutional for the government to prohibit the use of birth control in 1965. Though of course this was just for married couples. It did't become universally legal for unmarried people to buy birth control until 1972.