I have heard said that the opposition of the church to any form of contraception - or any attempt to prevent conception (pulling out, oral sex, etc.) while still performing coitus - was originally based in an outdated and wrong scientific view that sperm contained a fully formed human fetus that would mature in the womans uterus. (See: This Wiki Link for an overview).

The theory goes that strong opposition to contraception by church leaders was based on the view that wasting sperm is equivalent to killing a tiny, but fully formed human being - a conclusion reached due to incorrect and outdated scientific theory.

I was wondering if there is any truth to that claim?

note: Obviously, The church no longer advocates this view, I'm interested in the historical aspect behind the policy against contraception.

EDIT: I have heard this theory told to me before, but wrote it off as nonsense/urban legend. What prompted me to ask this question is that it was repeated on the rational wiki page on contraception . While not as big as a wiki as wikipedia, it does have a sizable audience, and for a wiki that purports to be anti-antiscience and anti-pseudoscience, having an unsubstantiated claim goes against its mission - especially since this article was featured on the front page recently.

To clarify - Contraception, means any natural or artificial method to prevent conception except for abstinence.

  • I've tried to make the question explicitly about the origin of the policy, not the current policy (as discussing that would be somewhat off-topic here).
    – Mad Scientist
    Jul 4, 2011 at 10:25
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    1) This claim does not seem to be notable. 2) The church documents (at least from 1900 and later, I am not familiar with older ones) about this are not based on the theory you are mentioning in any way. You may disagree with the arguments they use, but they definitely do not use the argument you present here.
    – Suma
    Jul 4, 2011 at 11:02
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    @Suma it is mentioned uncited at rational wiki (rationalwiki.org/wiki/Contraception#Opposition_to_contraception), but I've heard it before that (RW reminded me of the claim) as for 2) Fabian removed the phrase to the effect that church opposition since then has been standard church dogmatism and corporate momentum, he removed it to prevent discussion of 'current' church policy - I'm interested in the origin of the policy
    – crasic
    Jul 4, 2011 at 11:08
  • To make the historical intent clear, I would suggest to rephrase it more into the past, like "was based" instead of "is based".
    – Suma
    Jul 4, 2011 at 11:10
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    Having spent the time to answer it, I now see @Suma's comment suggesting the claim isn't notable, and I agree. @crasic, can you please update the question with an example of where you heard this to satisfy me that I didn't spend that effort on some nonsense claim by Cliff Clavin.
    – Oddthinking
    Jul 4, 2011 at 12:54

3 Answers 3



This can be shown with some simple history.

The ban on male contraceptives dates back to the Talmudic tradition.

Kathleen O'Grady, in Contraception and religion: A short history explains:

Genesis 38:9-10, states that during intercourse Onan "spilled his seed on the ground" (coitus interruptus). This was "evil in the sight of the Lord" and was punished by Onan's death. Jewish Talmudic literature builds on this passage and prohibits the use of any contraceptive device for use by men which would waste the "male seed"

O'Grady doesn't seems cite a reference for this exact claim, but gives a number of references at the end, and this particular one appears to come from the footnotes of Humanae Vitae: A Generation Later which seems like a good historical reference (perhaps politically biased) for this area.

While the Spermist theory dates back to Pythagoras, the idea of homunculi came about during the Renaissance, and is generally ascribed to Nicolaas Hartsoeker (1656-1725). (Yeah, it's only a Wikipedia link, but not a particularly extraordinary claim. It cites: Hill, K.A. (1985). "Hartsoeker's Homonculus: a corrective note". Journal of the History of the Behavioral Sciences 21 (2): 178–179. doi:10.1002/1520-6696(198504))

So opposition to contraception predates homunculi.

I am no theologian, but the modern arguments against contraception by the Catholic Church appear to be based on an 1968 Encyclical by Pope Paul VI, Humanae Vitae which contains no mention of homunculi.


The immediate origin of the policy is Old Testament (the story of Onan) and is basically a legal interpretation of the overarching principle of "be fruitful and multiply".

The first mitzvah (commandment from God) in the Torah states: "And God blessed them and said to them, 'Be fruitful and multiply; fill the earth and subdue it'" (Genesis 1:28).

The origin of the ""be fruitful and multiply" is 100% clear if you think from game theory point of view - in the times before 1000BC, with low population density, low productivity and high mortality, the society which carried the birth control meme was at best easily out-competed by the one that carried "as many children as possible" meme; and at worst simply died out on its own.

Please note that this logic is independent of anyone's view on whether Genesis was a literal word of G-d, or divinely inspired work, or a set of codified moral rules, or a work of fiction.

In addition, on an individual level, a fairly un-nuanced evolutionary explanation is that an average male had VERY low chance of procreation (most males left no descendants) and therefore if you HAD a chance to score, and didn't use it, your memes and genes that predisposed you to use birth control didn't survive. I don't have a more scholarly cite handy, but from http://tierneylab.blogs.nytimes.com/2007/08/20/is-there-anything-good-about-men-and-other-tricky-questions/, quoting Dr. Baumeister, a prominent social psychologist who teaches at Florida State University:

The “single most underappreciated fact about gender,” he said, is the ratio of our male to female ancestors. While it’s true that about half of all the people who ever lived were men, the typical male was much more likely than the typical woman to die without reproducing. Citing recent DNA research, Dr. Baumeister explained that today’s human population is descended from twice as many women as men. Maybe 80 percent of women reproduced, whereas only 40 percent of men did.

  • 100% clear seems to be an exaggeration to me. I'm sure, you don't have exact numbers for those time, and how do you exclude different influences and reasons? For example the high risk of mothers to die during birth, or the probability to be caught, if the man did copulate with a woman which wasn't his own. Jul 4, 2011 at 20:36
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    @user - what does that have to do with anything? "high risk of mothers to die during birth" == the risk wasn't high enough to offset the payoff of extra child. and "getting caught" is fully irrelevant to contraception, OR propagating ones genes. If you choice is to die old and childless or young and with children, the winning strategy is #2.
    – user5341
    Jul 5, 2011 at 1:50
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    If you have red hair, and the child of your neighbor is red haired, but its `parents' have black hairs, and you get killed for sleeping with the wrong woman, and end without children therefore... . Or the mother of 8 childs dies, which could decrease the chance of all the existing childs to grow up healthy. Jul 5, 2011 at 2:14

I'm extremely sceptical that St. Thomas Aquinas - or for that matter St. Augustine - had any notion of 'the wee man', because in the 1000 years of Christendom before the renaissance, there wasn't a lot of interest in human anatomy or microscopy.

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    @Odd Is it standard practice on this site to remove two-thirds of an answer that's not yours?
    – user11643
    Feb 18, 2017 at 3:24
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    I also find correcting my grammar to be exceptionally fruitless. Feb 18, 2017 at 3:25
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    [I posted a comment here earlier, but it doesn't seem to have stuck :-( Trying again.] The policy for editing is "Be bold", so if two-thirds of an post is detracting from the actual answer, yes, it is standard practice. The answer isn't "yours" any more. I'm not fussed if you care about grammar; those edits are to make the site accessible for others who need more clarity.
    – Oddthinking
    Feb 19, 2017 at 23:44

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