Because most philosophies that frown on reproduction don't survive.

Thursday, May 15, 2008

Random Biological Thought of the Day

One of the things that sets us apart from our close genetic relatives among the large primates is that human females do not have obvious visual queues as to when they are fertile. Sure, as every NFP using couple knows, with enough study we can figure these things out with a fair degree of accuracy. But it's certainly not something where you can simply look at your wife from across the room and see, "Ah, fertile at the moment, are we."

By comparison, when researchers are watching bands of chimps, the physical signs of a female chimp becoming fertile are so obvious that the researches can spot them from a distance. And the male chimps certainly are not in any doubt. (Of course, it helps in this regard that chimps don't wear clothes, but you get the idea.)

It strikes me that as humans became, well... human, and our social structures began to develop, that the fact that it's not readily obvious when women are and are not able to conceive probably helped to re-enforce the need for marriage (or stable mating arrangements, if you want to sound all analytical about it) and for family social structures. This lack of certainty created a need for social structures that emphasized long term fidelity.

Thinking about it this way: our lack of certainty as to whether any given act of intercourse will lead to children is one of the aspects of the human creature which had a fundamental influence on how societies developed. Or put it in moral terms: this physical reality reflects the intention that families be based on permanent fidelity.

All of which suggests that the advent of generally effective birth control would be very socially disruptive. (Which I think one could certainly argue it has.) And that if 100% effective artificial birth control were developed (which could be turned off and on at will yet allowed no user error or failure) it would be even more socially destructive.

In a strictly cultural sense: the social structures we're used to surrounding marriage and the family are based on the assumption of not knowing when sex will result in offspring. In a moral sense: that physical reality reflects that we are creatures who are made to work a certain way -- and our morals surrounding marriage are the "operating manual" for how to live successfully within that reality.

When we change these things, we in some real sense change who we are.


bearing said...

It's not just our "hidden" fertility that sets us apart. In many (most?) mammalian species, the females are sexually unreceptive or even incapable of mating when they are not in estrus.

Anonymous said...

But if knowledge of fertile periods is the issue, then shouldn't the use of fertility tracking, as in NFP, be just as problematic as the use of artificial birth control?

Kate said...

Your analysis makes sense to me, as our fertility signs are ones which are only really easy to pick up on in close quarters and with a great deal of familiarity. This definitely suggests that the advantage (reproductively) goes to men capable of long term commitment.

(This goes to the comment from 'a philosopher' as well. Human women don't have non-existant fertile signs, we have non-obvious ones. NFP is an evolution of the sort of understanding possible only in a committed relationship, and is certainly not comparable with the assumption of infertility/ fertility control that goes with artificial birth control)

The other interesting part is that this levels the playing field. In species (like baboons) where fertility is on display the strongest and (often) most brutal male is the one who can fight off the others and win the 'prize' of the fertile female. Hidden fertility seems to give the female more freedom to choose a mate for other reasons, such as stability and childrearing qualities, rather than merely brute strength.

Anonymous said...

Excellent post! I've heard something of the opposite suggested: a woman's ability to be sexually active at any point of her cycle is because of permanent human relationships, not a result of it -- the idea being that frequent intercourse improves the male's commitment to the female.

Bonobos are in some ways more similar to us than chimpanzees are: females can be sexually active virtually all the time. But sex in their society plays a very different role from that which it plays in ours. That suggests that something about what is best for humans sexually is written in our minds and hearts, not just arising from the biology of sex.

CMinor said...

While I don't have any alternate scenarios to propose, I'm inclined to be skeptical of the "lack of fertility awareness lead to monogamy" hypothesis for a couple of reasons:
1. Menstrual synchrony. Which happens when a group of females of reproductive age lives together in close association.
2. Lunar cycles. In communities without artificial light, the women tend to all menstruate at the new moon and ovulate at the full. Been doing it from time immemorial.

Within a primitive community, I think it's plausible that all the women became fertile at around the same time every month. Also, there is evidence that some primitive communities had an understanding of the significance of the mucus symptom (see Mary Shivanandan's Natural Sex.)

The impression I got about this particular hypothesis was that it rested on the assumption that no one in a group of primitive humans could be sure when a given female became fertile, therefore monogamy was essential to males in order to ascertain which children were theirs.

I really can't think of any good reason why a group of humans with intelligence parallelling that of modern humans, living close to nature, should be presumed unaware of either fertility signs or the connection between fertility and pregnancy given the factors I mentioned above. On the other hand, I can think of a few reasons why modern-day anthropologists might suffer from a touch of cultural blindness about female fertility as it was pre-20th C.