# When did man realize that pregnancy was a direct result of sex? **URL:** \ **Category:** Factual Questions\ **Created:** [July 14, 2009, 6:57pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016 "2009-07-14T18:57:48Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![bibliophage](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bibliophage/32/7615_2.png) [@bibliophage](https://boards.straightdope.com/u/bibliophage)\ **Post date:** [July 14, 2009, 11:52pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/21 "2009-07-14T23:52:55Z")
> [@MPB\_in\_Salt\_Lake](#): > > I am almost sure that ol’ Cecil wrote a column on this, many moons ago… He did indeed: [When did mankind figure out that SEX = BABIES? - The Straight Dope](http://www.straightdope.com/columns/read/734/when-did-mankind-figure-out-that-sex-babies) ---
**Author:** ![Pedro](https://avatars.discourse-cdn.com/v4/letter/p/919ad9/32.png) [@Pedro](https://boards.straightdope.com/u/Pedro)\ **Post date:** [July 14, 2009, 11:56pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/22 "2009-07-14T23:56:19Z")
I’d say it was when humans gained the cognitive ability to understand abstract concepts like pregnancy and sex and use logical implication. Even in the animal world the connection is there, in mating rituals and partner selection, just not in a cognitive sense. ---
**Author:** ![Malleus\_Incus\_Stapes](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/malleus_incus_stapes/32/3293_2.png) [@Malleus\_Incus\_Stapes](https://boards.straightdope.com/u/Malleus_Incus_Stapes)\ **Post date:** [July 15, 2009, 12:30am UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/23 "2009-07-15T00:30:57Z")
> [@friedo](#): > > The seed-spilling guy is Onan, which is why the old-timey term for jacking it is onanism. The term “onanism” was coined by people who didn’t look too closely at the text; Onan’s act was coitus interruptus, not masturbation. ---
**Author:** ![Dallas\_Jones](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dallas_jones/32/3277_2.png) [@Dallas\_Jones](https://boards.straightdope.com/u/Dallas_Jones)\ **Post date:** [July 15, 2009, 12:58am UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/24 "2009-07-15T00:58:19Z")
> [@gazpacho](#): > > If you have domesticated animals it is pretty obvious that sex leads to babies. I would say the knowledge predates writing by a long time. Yes, even very primitive humans would have understood the life cycles of their prey. Most of these prey animals have definite mating and birthing seasons. The cause and effect would have been obvious. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [July 15, 2009, 1:14am UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/25 "2009-07-15T01:14:16Z")
> [@ghardester](#): > > Yes, even very primitive humans would have understood the life cycles of their prey. Most of these prey animals have definite mating and birthing seasons. The cause and effect would have been obvious. Not really, because animals all have different gestation periods. So while the buffalo and hare and antelope were all bumping uglies in autumn the buffalo were giving birth the following summer, whereas the sheep were giving birth in spring and the hare were giving birth next month. The cause and effect really isn’t obvious unless you already know that sex is what leads to pregnancy. ---
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [July 15, 2009, 1:28am UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/26 "2009-07-15T01:28:58Z")
> [@brewha](#): > > …Unfortunately, googling ‘sex’ doesn’t do much to answer this question… Really? Huh. Did you find anything else interesting? ---
**Author:** ![JRDelirious](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jrdelirious/32/9531_2.png) [@JRDelirious](https://boards.straightdope.com/u/JRDelirious)\ **Post date:** [July 15, 2009, 1:42am UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/27 "2009-07-15T01:42:54Z")
> [@Skald\_the\_Rhymer](#): > > Onan. He had been obliged to marry his dead brother’s widow. Any children of that levirate marriage would have been considered his brother’s heirs rather than his own. Why this vexed him is not made clear Onan was a selfish bastid who would rather make it appear that Tamara was “barren” (meaning that she would be discredited and could be even cast out, with little opportunity for remarriage into another family) and there’d be no descent whatever from his brother and he would get some of that late brother’s inheritance. Eventually all the surviving sons were so spooked that Tamara had to fool Judah himself into doing the deed by posing as a harlot. \*And this is the book where we’re supposed to learn morals?😉 \* The “seed” metaphor (which is where the word “semen” comes from) would seem appropriate to the many peoples in the sense that, like seed, it sometimes takes and it sometimes doesn’t. Women were considered to be “fertile” or “barren” as to whether they’d provide a proper environment for the seed to take hold and it was seldom assumed that maybe the man was shooting blanks, it was always her fault. ---
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [July 15, 2009, 2:49am UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/28 "2009-07-15T02:49:44Z")
> [@JRDelirious](#): > > …The “seed” metaphor (which is where the word “semen” comes from) would seem appropriate to the many peoples in the sense that, like seed, it sometimes takes and it sometimes doesn’t. Women were considered to be “fertile” or “barren” as to whether they’d provide a proper environment for the seed to take hold and it was seldom assumed that maybe the man was shooting blanks, it was always her fault. That’s a really good point. I’d never thought of it that way before, but I suspect you’re right. ---
**Author:** ![Dallas\_Jones](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dallas_jones/32/3277_2.png) [@Dallas\_Jones](https://boards.straightdope.com/u/Dallas_Jones)\ **Post date:** [July 15, 2009, 3:20am UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/29 "2009-07-15T03:20:33Z")
> [@Blake](#): > > Not really, because animals all have different gestation periods. So while the buffalo and hare and antelope were all bumping uglies in autumn the buffalo were giving birth the following summer, whereas the sheep were giving birth in spring and the hare were giving birth next month. The cause and effect really isn’t obvious unless you already know that sex is what leads to pregnancy. Well, this isn’t really debate worthy, it’s a question in General Questions that cannot have a definitive answer. I will just explain my viewpoint. I don’t know where you live or if you hunt, or have lived on a farm. But the mating seasons and life cycles of animals in the wild or captivity are quite obvious when you are part of their environment and see the behavior. The point I was making is that early humans lived in the same environment as their prey and would understand the reason for the mating season. Knowledge of their environment and the animals in it could not be avoided. Children on farms figure out the connection very early without knowing the particulars of gestation times, or having it explained to them in scientific terms. The original OP’s question was when did man (humans) realize that pregnancy was a result of sex. I don’t see it as some discovery, I see it as something known from the dawn of awareness. ---
**Author:** ![jackdavinci](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackdavinci/32/3259_2.png) [@jackdavinci](https://boards.straightdope.com/u/jackdavinci)\ **Post date:** [July 15, 2009, 9:32am UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/30 "2009-07-15T09:32:19Z")
Can’t cite because I read it a long time ago, but I read that some early humans had an idea of sex=pregnancy but it took much longer to figure out the idea of specific paternity. I think it might have had something to do with theories about matriarchal groups converting to patriarchal because of this insight. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [July 15, 2009, 9:49am UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/31 "2009-07-15T09:49:33Z")
> [@ghardester](#): > > The point I was making is that early humans lived in the same environment as their prey and would understand the reason for the mating season. Knowledge of their environment and the animals in it could not be avoided. Which is simply begging the question. They understand the reason for the mating season, and as a result can work out the gestation periods of the animals. IOW they can only work out that mating causes births after they already have that piece of information. > [@](#): > > Children on farms figure out the connection very early without knowing the particulars of gestation times, or having it explained to them in scientific terms. Children don’t figure out the connection at all. They get told. Not in scientific terms, but the first time they see two animals copulating they are told that they are making baby animals. There’s absolutely no way that a child could work that out for themselves. > [@](#): > > The original OP’s question was when did man (humans) realize that pregnancy was a result of sex. I don’t see it as some discovery, I see it as something known from the dawn of awareness. Which is provably not true. Cecil did a column on this subject that I can’t be bothered to find. In it he lists numerous human cultures that were completely unaware that sex led to pregnancy, including at least some Australian Aborigines and some Polynesians. If some peoples were unaware that sex led to pregnancy even in the 19th century, how can it possibly be something known since the dawn of awareness? Are you proposing that some people forgot this piece of information? ---
**Author:** ![Malacandra](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Malacandra](https://boards.straightdope.com/u/Malacandra)\ **Post date:** [July 15, 2009, 10:35am UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/32 "2009-07-15T10:35:49Z")
> [@JRDelirious](#): > > Onan was a selfish bastid who would rather make it appear that Tamara was “barren” (meaning that she would be discredited and could be even cast out, with little opportunity for remarriage into another family) and there’d be no descent whatever from his brother and he would get some of that late brother’s inheritance. > > Eventually all the surviving sons were so spooked that Tamara had to fool Judah himself into doing the deed by posing as a harlot. \*And this is the book where we’re supposed to learn morals?😉 > \* Yes indeed, but not always from the supposition that the players in the story were acting morally. When Judah found out that Tamar was several months gone he was about to have her put to death as a whore and fornicator, until she presented him with the receipt (some of his personal effects), at which point he manned up and said “Ya got me. Folks, this woman’s no more to blame than I am, and she’s to be treated right, you hear?” - which is a “Go thou and do likewise” story if ever there was one. ---
**Author:** ![Shodan](https://avatars.discourse-cdn.com/v4/letter/s/9f8e36/32.png) [@Shodan](https://boards.straightdope.com/u/Shodan)\ **Post date:** [July 15, 2009, 12:16pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/33 "2009-07-15T12:16:27Z")
> [@pravnik](#): > > There have been cultures in recent history that didn’t make the connection between sex and pregnancy. Anthropologist Bronislaw Malinowski reported in the early 20th century that Trobriand islanders believed that pregnancy was caused by spirits entering the womb as women bathed in the lagoon. I read an anthropology text that suggested that the Trobriand Islanders were having a joke at the expense of the poor dumb white guy. FWIW. Regards, Shodan ---
**Author:** ![astorian](https://avatars.discourse-cdn.com/v4/letter/a/ad7895/32.png) [@astorian](https://boards.straightdope.com/u/astorian)\ **Post date:** [July 15, 2009, 2:43pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/34 "2009-07-15T14:43:56Z")
> [@Shodan](#): > > I read an anthropology text that suggested that the Trobriand Islanders were having a joke at the expense of the poor dumb white guy. FWIW. > > Regards, > Shodan Entirely possible- more than a few elderly Samoan women have talked about that earnest but dim Margaret Mead, and how she swallowed every nonsensical story they concocted for her. ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [July 15, 2009, 3:25pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/35 "2009-07-15T15:25:31Z")
I got interested in this subject a few years ago and read up on it, concluding that there are recent - indeed, at the time, current - societies that did not believe intercourse was the cause of pregnancy. Whether any particular examples were in ernest or in fun, this is perfectly plausible. In the typical course, humans change in their behaviors and forms as life proceeds. Intercourse and pregnancy are but two of the various milestones along this path. It is possible to draw a connection between the two, of course. But if all of them are typical, it is not easy to choose particular pairs of milestones to associate. Moreover, because of our social activity, it would not be unusual to keep romantic liasons a secret, which means that the visible examples of others in your own group would include both people who had had intercourse but not become pregnant, and people who (to your knowledge) have not had intercourse but did become pregnant. Recognizing this latter situation as some kind of fraud only works after you decide intercourse is a prerequisite, and reasoning that the latter situation being fraudulent would demonstrate intercourse as a prerequisite is circular reasoning. ---
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [July 15, 2009, 5:22pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/36 "2009-07-15T17:22:07Z")
> [@Blake](#): > > …Cecil did a column on this subject that I can’t be bothered to find… May I suggest checking just ten posts before your own? 😉 ---
**Author:** ![nightkin](https://avatars.discourse-cdn.com/v4/letter/n/a3d4f5/32.png) [@nightkin](https://boards.straightdope.com/u/nightkin)\ **Post date:** [November 5, 2012, 1:32pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/37 "2012-11-05T13:32:18Z")
around 12,000 years ago Man was keeping domesticated dogs that were almost certainly bred from wolves using selective breeding. this would suggest that by that time Mankind was aware of the link between sex and pregnancy. Humans are by nature very cognitive, and would be able to draw conclusions based on observations. it would only take a few decades of misinterpretation before they finally hit upon the truth. We generally learn about ourselves by observing animals, and the domestication and deliberate breeding of animals would suggest that our cave dwelling ancestors knew that sex eventually leads to pregnancy - or at least that the lack of sex excludes pregnancy. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [November 5, 2012, 2:03pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/38 "2012-11-05T14:03:18Z")
I would suspect that the connection was guessed very early. After all, there is only one thing (we hope) going in, and only one thing coming out. Even a zombie would make the connection with what little Braaaaaiiinzzz! they had. Filling in the details - must be past puberty, doesn’t happen every time, junior looks like dad (usually) etc. - just icing on the cake. I suspect a lot of the “they did not know” are either just so stories, like the moon is made of green cheese; or the culture experienced a major disconnect in their oral cultural traditions, a major die-off of adults or some such. ---
**Author:** ![njtt](https://avatars.discourse-cdn.com/v4/letter/n/ecd19e/32.png) [@njtt](https://boards.straightdope.com/u/njtt)\ **Post date:** [November 5, 2012, 4:14pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/39 "2012-11-05T16:14:51Z")
> [@Chronos](#): > > Another issue is heritence. It doesn’t take long for folks to realize that a baby bears a certain resemblance to the woman that baby came out of, and also bears a similar resemblance to the man who’s routinely having sex with that woman. Any model of pregnancy must take this observation into account somehow On the contrary, many of the “primitive” pre-literate cultures studied by anthropologists have turned out to be _matrilineal_. In such cultures, families are structured around the female line, and the responsibility of a father for his children’s welfare (even if his identity is known) is not recognized, or is de-emphasized. He may not even live with the children and their mother, but may stay with his mother’s family. This is not, however, the same thing as a “matriarchal” society; leadership and control of property in matrilineal societies generally still belongs to men, just not to fathers _qua_ fathers. Instead, of the father, the maternal uncle is considered the head of his sister’s family, and is considered to be responsible for her children’s welfare. Likewise, inheritance of property passes from the uncle to his sister’s sons. Several matrilineal societies of this sort were around recently enough to be studied by anthropologists in the 19th and 20th centuries. Probably, a few still remain in remote parts of the world. Whether or not they recognize the biological role of fathers now, it seems highly likely to me that they did not do so at the time that their way of structuring family authority, responsibilities, and inheritance became established, and very likely this was in relatively recent times. This is because, once the biological role of fathers does become recognized, it seems likely that they will soon be expected to take more responsibility for their children, and will also expect to have some authority over them. Thus, once the biological role of fathers is recognized, a matrilineal family system will probably start to evolve towards being a patrilineal one. Most human societies, including most “primitive” ones, are patrilineal, which suggests that they discovered the biological role of fathers long ago, but matrilineal societies probably realized it only fairly recently, if at all. ---
**Author:** ![njtt](https://avatars.discourse-cdn.com/v4/letter/n/ecd19e/32.png) [@njtt](https://boards.straightdope.com/u/njtt)\ **Post date:** [November 5, 2012, 4:31pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/40 "2012-11-05T16:31:45Z")
> [@nightkin](#): > > around 12,000 years ago Man was keeping domesticated dogs that were almost certainly bred from wolves using selective breeding. I do not think that there is much reason to believe that dogs became domesticated via deliberate selective breeding. Some of the more docile wolves, and the ones who were less frightened of humans, probably started hanging around human encampments as scavengers. The more aggressive wolves would have been driven off by the humans, but less aggressive ones would have been tolerated. The less aggressive, more human-tolerant wolves would have tended to interbreed preferentially with each other simply because they were close to each other, living around the human encampments, whereas the more aggressive wolves would have been breeding with each other somewhere else. This would tend to make the wolves living close to the humans even more human friendly (and the other ones even less so), and the process would accelerate until wolves and dogs became clearly distinct. No human understanding or agency need be involved beyond the driving off of more aggressive, troublesome wolves, and the recognition that non-aggressive ones were not worth the driving off. [Previous page](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016.md?page=1) [Next page](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016.md?page=3)