Hank Green: Alright, everybody. (blows whistle) Settle down. Babies. They're the reason we have sex. And yet, also the least common reason we have sex. Seriously, in 1997, researchers gave a group of folks a list of eight reasons why they might want to have sex, and had them rank them from one to eight, and to have a baby ranked eighth out of eight reasons to have sex. The fact remains, kids, that baby conception is the reason that our bodies do the sex thing to begin with. So common side effect of skoodilypooping, as my brother John calls it, uh, is baby-having, so we've spent a lot of time trying to figure out how to indulge in the skoodilypooping part while forgoing the baby-making part. And today we're going to talk about the past, present, and future of how people try to have sex without having babies. Uh, and this is not a relationship or sexual advice film, you can get that from your real gym teacher.

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Throughout history, our ancient friends from all over the world had a bunch of colorful ideas about how to prevent getting knocked up, and their desperation was palpable. For instance, in Ancient China, women drank cocktails of lead and mercury to keep them from getting pregnant, which was actually very effective, because you can't get pregnant when you're dead. In Medieval Europe, magicians recommended that ladies who did not want to get pregnant strap a weasel testicle around one of their thighs, which was also extremely effective, because who would go within a mile of that? If you don't have any weasel testicles on hand, a necklace made from the severed foot of a weasel might work, or you know, possibly the anus of a hare. Anus of a hare, that was a very, very popular homeopathic remedy for the pregnancy thing. There's also one I particularly like from the olden days of Canada, where frontierswomen swore by a liquor made of beaver testicles soaked in moonshine. They drank this stuff like water, so they didn't have to be baby mama to a horny old fur-trapper. Sounds reasonable to me.

Anyways, these antiquated methods for keeping women from getting pregnant are pretty stupid. And you know, they weren't based on any real understanding of how lady business works. But there were some remedies that were at least successful enough at their job that women kept using them. Take, for example, silphium, an ancient plant that seemed to have real contraceptive and abortifacient properties. Around 2600 years ago, the Greek island of Thera was becoming overpopulated. At pretty short order, the Cyrenians discovered silphium, this weed in the fennel family that was growing in the hillsides around town. And they were suitably impressed by the plant, not only because it was a delicious garnish to goat tenderloin, it was also really good at keeping women from getting pregnant and from preventing pregnancies from progressing. Pretty soon, uh, the ancient versions of gynecologists had women drinking the juice of the silphium plant once a month, or just kind of wedging some wool that had been soaked in, like, silphium juice up, you know, up there. And silphium was all the rage. The Cyrenians were exporting it all over the place. And though we can actually document the decreased birth rates in Ancient Rome during silphium's heyday, we will never know how effective it actually is, because dammit, if the Ancients didn't hump it into extinction. Let's just say the Cyrene's silphium industry did very well. As a matter of fact, all Cyrenian currency was stamped either with a picture of the silphium plant itself, or with a heart-shaped C, which may be where we got the modern valentine shaped heart-symbol. Or, there's a picture of a lady pointing to a silphium plant with one hand, and at her genitals with the other. Nobody ever said that the Ancients were subtle. Anyway, within about 50 years, silphium was just a memory due to aggressive over-harvesting. A little tear.

So during some periods in history, birth control could make or break economies, but in others, like right after the black plague finished having its way with Europe in the 14th century, any attempt at putting the breaks on population growth was punishable by death. In fact, the church got involved, as it was wont to do back in the 14th century, and started making a big fuss about how wasting semen was a sin and an abomination against nature, and in 1484, Pope Innocent VIII issued an order commonly referred to as The Witch-Bull of 1484, in which he recognized the existence of witches, a.k.a. women who knew about birth control and other useful things like how to safely deliver a baby and gave his approval to correct, imprison, punish, and chastise witches accused of having, quote, 'slain infants yet in the womb and of hindering men from performing the sexual act and women from conceiving.' So basically, the Pope made contraception and abortion illegal, and lots of people got killed for it, including lots of midwives and folks who actually knew what they were doing and were trying to make everybody's lives better.

So luckily for all of us, over the last few hundred years, our knowledge of the human reproductive system has grown and our birth control methods have become a lot safer and more reliable. Modern birth control can be divided up into a few categories: sterilization, barrier methods, hormonal methods, and contragestion. And of course, you've got your good old fashioned abstinence, which works 100% of the time if you tie a weasel testicle around your leg.

So I'll start with sterilization, because as a mechanism, it's sort of the most obvious. Basically, you take the female Fallopian tubes, or the male vas deferens, both structures that allow the transport of sex cells, the sperm or the eggs, from the place where they're stored, to the place where they get their fertilization on. And you just snip them, or you clamp 'em or block 'em or die 'em up some way. Now you hear about people sometimes having these surgeries undone, but these procedures are considered permanent, so when you decide to get sterilized, it'd be a pretty good idea to make sure you damn well don't want a baby.

Now with barrier methods, the idea is to block the sperm before it gets through the cervix and to the egg, so condoms, diaphragms, fit into this category. In fact, even though nobody even knew about sperm until like, the mid 15th century, people have been suspicious about the role that semen played in the whole pregnancy situation for a long time. In fact, there are cave paintings in France dating back to around 15,000 BC depicting condom use. Well, I mean, probably, it's kinda hard to tell, it's going on in a cave painting. We're also pretty sure that Ancient Romans had condoms and so did the Ancient Egyptians, the thing is, a lot of times, these beta-version condoms were made of like, oiled silk paper or lamb intestines, so, you know, not 100% effective. Quality products made from quality materials!

 Though fast forward, quite fast, to the 1950s, when some American drug companies started researching a way to make synthetic progesterone, a hormone that helps regulate the female menstrual cycle. By the early 1960s, they had developed the first oral contraceptive, a big honkin' horse pill of hormonal goodness which was far from perfect but it was pretty reliable at making you not have a baby. And the ladies of the 1960s were pretty frickin' psyched. Loretta Lynn even wrote one of her more awesome songs about how much she loved the pill because she was sick of being so damn pregnant all the time. Anyways, these days, we've got all kinds of hormonal birth control methods like the pill, hormonal implants, shots, patches, rings, hormone laced IUDs (we'll get to IUDs in a minute), basically all these things just release synthetic estrogen and/or progesterone into a woman's system at the right time each month, essentially preventing her ovaries from releasing eggs or from making her womb sort of an inhospitable environment for fertilized eggs. In this way, hormonal methods of contraception are like barrier methods, they prevent the sperm and egg from ever meeting each other, in fact, the word contraception literally means 'against fertilization'.

Now we come to contragestive methods, like intrauterine devices or IUDs, and they allow the sperm to fertilize the egg, but prevent the fertilized egg from implanting on the wall of the uterus. So contraception means against fertilization, contragestion means against gestation. The most common contragestive method of birth control comes in the form of IUDs, though IUDs kind of straddle the line, as it were, between contragestion and contraception. That is a hard word to say. IUDs are these T-shaped pieces of plastic covered with coiled copper wire that are inserted directly into the uterus. Some of them release low levels of synthetic progesterone as well. Interestingly, how IUDs work is still a little bit of a mystery, nobody can quite figure out what's going on, but it looks as though partially, the coiled copper works as a spermicide to kill all the sperm before they can ever find the egg, also, IUDs kind of inflame the area, which means that there are a lot of white blood cells which uh, somehow start attacking the sperm and even a fertilized egg.

So these days, we've got a bunch of different options for birth control, and you'd think we'd be satisfied, but we're not, we want more! So the future of birth control is looking pretty space-age. All kinds of crazy things are being tested, like a hormone gel that women rub on their bellies instead of taking the pill, and also one-off hormone treatments for women that can be taken, you know, as needed instead of constantly. However, researchers are looking into things like using ultrasound to like, zap the fertility out of men's testicles, which doesn't sound particularly fun, or potentially a male pill or injection of a sort of a huge amount of testosterone that would make your sperm producing parts be like, 'well, I've produced all the sperm!' and then they just stop. But do we want a bunch of infertile testosterone jacked men walking around the world? I'm not sure, but, you know, options are good.

Thank you for watching SciShow, if you would like to ask us questions, uh, please do so in the comments below, if you would like to suggest other topics, uh, like this one about birth control, um, but I will not be giving you advice on what you should do with your personal reproductive life, so that's up to you, science does not make those decisions. We'll be down in the YouTube comments and on Facebook and Twitter, and we'll see you next time.

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