# When did man realize that pregnancy was a direct result of sex?
**URL:** https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016
**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:** 1
### Author:  [@brewha](https://boards.straightdope.com/u/brewha)
#### Post date: [July 14, 2009, 6:57pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/1 "2009-07-14T18:57:48Z")
Not really much to elaboration needed on the thread title. The earliest documentation[sup]\*[/sup] I can think of is that Jesus’s mom’s virgin pregnancy was considered odd. So, sex= pregnancy has been a known concept for at least 2000 years (give or take)
Here’s my thinking. If we go back far enough, the human race is just monkeys doin the nasty[sup]\*\*[/sup]. Babies are born and raised on instinct with no rational thought as to why or how they are made.
Further down the line, these monkeys are more or less human have a conscious mind and language and still don’t know that it takes a sperm and an egg to get pregnant.
Then, someone puts 2 and 2 together and realizes that pregnancy only happens after sex. Who and/or when was this?
Unfortunately, googling ‘sex’ doesn’t do much to answer this question.
If this proves to be an unknown, I have no problem getting this shuttled over to IMHO, if people want to give their best guesses on it.
[sup]\*[/sup]not interested in discussing the accuracy of the bible or this lady’s virgin pregnancy. I only bring it up because someone wrote down, in a book, that this lady had a virgin pregnancy. Since the author thought that it was odd, I’m assuming that sex = pregnancy was know at the time.
[sup]\*\*[/sup] yes gross oversimplification. My point is that animals don’t know this cause/effect result. So, I’m assuming, if we look far enough back, this is something humans were unaware of.
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### Author:  [@Crotalus](https://boards.straightdope.com/u/Crotalus)
#### Post date: [July 14, 2009, 7:05pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/2 "2009-07-14T19:05:15Z")
The Bible actually moves the date back further than 2000 years. How far depends on what you believe about when Genesis was written.
[QUOTE= Genesis 4]
1 Adam [a] lay with his wife Eve, and she became pregnant and gave birth to Cain.
[/QUOTE]
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### Author:  [@Oakminster](https://boards.straightdope.com/u/Oakminster)
#### Post date: [July 14, 2009, 7:06pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/3 "2009-07-14T19:06:28Z")
I think the sex makes babies link is probably established in _Genesis_, and was likely well known before that book was written.
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### Author:  [@Hampshire](https://boards.straightdope.com/u/Hampshire)
#### Post date: [July 14, 2009, 7:08pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/4 "2009-07-14T19:08:07Z")
My guess would be that it’s just too far back to research or have any documentation on.
I’d be more interested in finding out when they realized what was happening at a microscopic level. The exsistence of an actual sperm + egg. Before that I wonder what type of theories floated about? All they knew was a man ejaculating semen into a woman created a baby. As far as what was in the semen and what the woman contributed besides a womb who knows?
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### Author:  [@gazpacho](https://boards.straightdope.com/u/gazpacho)
#### Post date: [July 14, 2009, 7:09pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/5 "2009-07-14T19:09:22Z")
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.
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### Author:  [@Oakminster](https://boards.straightdope.com/u/Oakminster)
#### Post date: [July 14, 2009, 7:10pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/6 "2009-07-14T19:10:51Z")
Think there’s some biblical language about that microscopic stuff too, at least in a limited sense. They refered to sperm as “seed”, and I seem to remember something about some guy spilling his seed on the ground so as to not knock up whoever he was boinking.
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### Author:  [@Zsofia](https://boards.straightdope.com/u/Zsofia)
#### Post date: [July 14, 2009, 7:13pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/7 "2009-07-14T19:13:17Z")
Oh, crazy shit, **Hampshire**. Theories included a little homonuculus in the sperm, which provided all of the material (and the woman just provided the incubator), for one that I can remember.
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### Author:  [@velaro](https://boards.straightdope.com/u/velaro)
#### Post date: [July 14, 2009, 8:05pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/8 "2009-07-14T20:05:36Z")
The mammal ovum was discovered in 1826. I’d guess that until then, the woman was usually seen as nothing but an incubator.
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### Author:  [@friedo](https://boards.straightdope.com/u/friedo)
#### Post date: [July 14, 2009, 8:19pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/9 "2009-07-14T20:19:13Z")
> [@Oakminster](#):
>
> Think there’s some biblical language about that microscopic stuff too, at least in a limited sense. They refered to sperm as “seed”, and I seem to remember something about some guy spilling his seed on the ground so as to not knock up whoever he was boinking.
The seed-spilling guy is Onan, which is why the old-timey term for jacking it is onanism.
While “seed” is a euphemism used all over the place for semen, with the obvious metaphor of planting a plant seed in the ground, nobody saw actual sperm cells until microscopes were invented. Ova were more easily spotted because many species’ eggs are visible to the naked eye, including humans eggs.
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### Author:  [@Mahaloth](https://boards.straightdope.com/u/Mahaloth)
#### Post date: [July 14, 2009, 8:19pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/10 "2009-07-14T20:19:20Z")
> [@brewha](#):
>
> Not really much to elaboration needed on the thread title. The earliest documentation[sup]\*[/sup] I can think of is that Jesus’s mom’s virgin pregnancy was considered odd. So, sex= pregnancy has been a known concept for at least 2000 years (give or take)
> .
Yeah, but that’s not even the earliest pregnancy = sex story in the Bible.
For example, David committed adultery with Bathsheba, got her pregnant, and tried to cover it up by having Uriah come home to have sex with her. When he wouldn’t do it because it was unfair to the other soldiers, David had him put on the front lines(essentially murdering him).
So they have known for a really long time!
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### Author:  [@Smeghead](https://boards.straightdope.com/u/Smeghead)
#### Post date: [July 14, 2009, 8:19pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/11 "2009-07-14T20:19:31Z")
It must have been obvious even in prehistory that only women (or female animals) that are sexually active get pregnant.
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### Author:  [@MPB\_in\_Salt\_Lake](https://boards.straightdope.com/u/MPB_in_Salt_Lake)
#### Post date: [July 14, 2009, 8:22pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/12 "2009-07-14T20:22:30Z")
I am almost sure that ol’ Cecil wrote a column on this, many moons ago…
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### Author:  [@Malleus\_Incus\_Stapes](https://boards.straightdope.com/u/Malleus_Incus_Stapes)
#### Post date: [July 14, 2009, 8:54pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/13 "2009-07-14T20:54:44Z")
> [@Hampshire](#):
>
> My guess would be that it’s just too far back to research or have any documentation on.
> I’d be more interested in finding out when they realized what was happening at a microscopic level. The exsistence of an actual sperm + egg. Before that I wonder what type of theories floated about? All they knew was a man ejaculating semen into a woman created a baby. As far as what was in the semen and what the woman contributed besides a womb who knows?
There’s a whole section on theories of babymaking in [Cats Are Not Peas](http://www.amazon.com/Cats-Are-Not-Peas-Genetics/dp/0387947965). Like **Zsofia** said, there was some pretty wacky stuff. The presence of sperm in semen wasn’t discovered until the invention of the microscope. I don’t remember when the ova was found. When they were both identifided, scientists were devided into the egg camp and the sperm camp, believing that only one was responsible for the formation of the baby. It was even suggested that sperm were parasites that happened to colonize semen. Weird stuff.
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### Author:  [@pravnik](https://boards.straightdope.com/u/pravnik)
#### Post date: [July 14, 2009, 9:02pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/14 "2009-07-14T21:02:43Z")
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.
> [@](#):
>
> First of all, everybody in Kiriwina knows, and has not the slightest doubt about, the following propositions. The real cause of pregnancy is always a baloma, who is inserted into or enters the body of a woman, and without whose existence a woman could not become pregnant; all babies are made or come into existence (ibubulisi) in Tuma. These tenets form the main stratum of what can be termed popular or universal belief. If you question any man, woman, or even an intelligent child, you will obtain from him or her this information. But any further details are much less universally known; one obtains a fact here and a detail there, and some of them contradict the others, and none of them seems to loom particularly clear in the native mind, though here and there it is obvious that some of these beliefs influence behavior, and are connected with some customs.
>
> …
>
> Another cycle of beliefs and ideas about reincarnation implies a pronounced association between the sea and the spirit children. Thus I was told by several informants that after his transformation into a waiwaia, the spirit goes into the sea. The first version obtained (quoted above) implied that the spirit, after having washed on the seabeach and become rejuvenated, is taken up immediately by a female baloma and carried to Kiriwina. Other accounts state that the spirit, after being transformed, goes into the sea and dwells there for a time. There are several corollaries to this version. Thus in all the coastal villages on the western shore (where this information was collected) mature unmarried girls observe certain precautions when bathing. The spirit children are supposed to be concealed in the popewo, the floating sea scum; also in some stones called dukupi. They come along on large tree trunks (kaibilabala), and they may be attached to dead leaves (libulibu) floating on the surface. Thus when at certain times the wind and tide blow plenty of this stuff towards the shore, the girls are afraid of bathing in the sea, especially at high tide.
From [Baloma, Spirits of the Dead in the Trobriand Islands](http://www.sacred-texts.com/pac/baloma/bal06.htm)
Previous thread: [When did we find out that sex = baby?](http://boards.straightdope.com/sdmb/showthread.php?t=371129&highlight=Trobriand)
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### Author:  [@dracoi](https://boards.straightdope.com/u/dracoi)
#### Post date: [July 14, 2009, 9:06pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/15 "2009-07-14T21:06:48Z")
I think it would be pretty hard for any self-aware human to miss the connection between sex and offspring and that we probably got the idea before we were self-aware. My guess is that asking this is like asking an individual “When did you realize you had toes?” They won’t know - they knew about toes before they had the cognitive ability to remember a time of not knowing.
Even prior to domesticated animals, humans had to have observed wild animals, most of which go through a mating season that’s pretty hard to miss. Any successful hunter (even a wolf or shark) “knows” that the season for sex precedes the season for getting pregnant or laying eggs.
I also tend to think we’d have observed it in our own species. Even if you believe in cave men carrying women off by their hair and treating them as mere property, you’d have to believe that some women were allowed to refrain from sex (for example, after the death of a partner or as some kind of priestess) or be unable to have sex (for example, due to extreme vaginismus or a birth-related injury). Even if we’re talking 1% of women, that’s enough to put together a theory that you could then test by practicing a little self control.
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### Author:  [@Heart\_of\_Dorkness](https://boards.straightdope.com/u/Heart_of_Dorkness)
#### Post date: [July 14, 2009, 10:36pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/16 "2009-07-14T22:36:27Z")
> [@dracoi](#):
>
> I think it would be pretty hard for any self-aware human to miss the connection between sex and offspring and that we probably got the idea before we were self-aware… I also tend to think we’d have observed it in our own species…you’d have to believe that some women were allowed to refrain from sex…or be unable to have sex. Even if we’re talking 1% of women, that’s enough to put together a theory that you could then test by practicing a little self control.
The thing is, sex != offspring in a tidy, one-to-one sense, even now. Just ask anyone trying to get pregnant. The woman, man, or both might be infertile or have low fertility, or the woman might miscarry for any number of reasons, many of which – illness, injury, eating toxic plants – would have been far more common in prehistory. Even with a normal, healthy pair of adults the timing has to be right. And even if certain women were “allowed” to refrain from sex, or even forbidden from it for whatever reason, they might well go ahead and have sex anyway. And of course, little kids engage in sex play just because it feels good, and so it seems at least possible that you might have some pre-pubescent sex happening.
So what you end up with is a much muddier picture: most (probably) people have sex, and some who do have babies, and some do not; and among those who “don’t” (;)) have sex some have babies, and some do not. I can easily see this being something that self-aware people could “miss”.
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### Author:  [@Johanna](https://boards.straightdope.com/u/Johanna)
#### Post date: [July 14, 2009, 10:53pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/17 "2009-07-14T22:53:42Z")
> [@](#):
>
> When did man realize that pregnancy was a direct result of sex?
A good while after woman realized it. :smack:
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### Author:  [@Chronos](https://boards.straightdope.com/u/Chronos)
#### Post date: [July 14, 2009, 11:17pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/18 "2009-07-14T23:17:27Z")
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
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### Author:  [@Heart\_of\_Dorkness](https://boards.straightdope.com/u/Heart_of_Dorkness)
#### Post date: [July 14, 2009, 11:39pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/19 "2009-07-14T23:39:32Z")
> [@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
True. But, as someone mentioned upthread, this can also be less obvious if 1) you’re dealing with a small, homogeneous-looking population, especially if there’s a lot of interbreeding, and 2) if there’s not just one man routinely having sex with a given woman.
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### Author:  [@Skald\_the\_Rhymer](https://boards.straightdope.com/u/Skald_the_Rhymer)
#### Post date: [July 14, 2009, 11:47pm UTC](https://boards.straightdope.com/t/when-did-man-realize-that-pregnancy-was-a-direct-result-of-sex/503016/20 "2009-07-14T23:47:39Z")
> [@Oakminster](#):
>
> Think there’s some biblical language about that microscopic stuff too, at least in a limited sense. They refered to sperm as “seed”, and I seem to remember something about some guy spilling his seed on the ground so as to not knock up whoever he was boinking.
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
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