Reproductive Advantage
Not if you look at the math
I read somewhere, and I have no idea where and I probably wouldn’t link to it if I did know, but you can google it, that some people are claiming that ‘homosexuality’ or, as I put it here, ‘Sodomy’, confers genetic advantage. At first glance, it seems utter nonsense that the practice of Sodomy, which obviously leaves its practitioners with no offspring (at least to the extent it is practised consistently), should lead to a genetic advantage. At second glance it is still nonsense, but a bit more interesting nonsense.
The theory goes something like this: Having a Sodomite in your family means that you have someone around who is not busy protecting his own offspring, so he can be helpful in increasing your genetic success. This will, in a roundabout way, increase his genetic success, since he shares some of your genes. By way of evidence, we are told of all sorts of species where a large proportion of individuals are non-reproductive, and yet contribute to the overall success of the group. Like bees. Or ants.
Not as dedicated
First of all, before we get to the actual math, let’s notice one huge flaw in this argument: Sodomites aren’t worker bees. They don’t get up every morning dedicated to the success of the hive. They don’t live every moment of every day ensuring that the queen bee will be able to successfully raise her brood of children.
On to the math
Now let’s get on to the math. Let’s throw in some wildly optimistic numbers. Let’s say that having a Sodomite brother increases a sister’s reproductive rate by 50%.[1] And let’s say that the average woman has four children. Feel free to use different numbers and send me your results.
So the initial family looks like this:
Mother + Father -> Sister + Brother (And another sister and brother, but we aren’t calculating them. Again, feel free to try differing dynamics. I will be showing the result with more than one sister below)
Now if we call the genetic makeup of the Brother as ‘A’, then the genetic makeup of the sister is ‘1/2A’.
Now lets look at the way regular reproduction works.
Sister + Husband -> Kid + Kid + Kid + Kid
Genetically that makes:
Sister (1/2A) + Husband (0A) -> Kid (1/4A) * 4
Or, mathematically, the genetic equivalent of the brother. (4*1/4=1)
But in this example, the brother gets married as well:
Brother + Wife -> Kid + Kid + Kid + Kid
and genetically:
Brother (A) + Wife (0A) -> Kids(1/2A) * 4
Or, mathematically, the genetic equivalent of two brothers. (4*1/2=2)
All told this generation would include, genetically, three brothers. Thus a man who reproduces normally, along with his sister who reproduces normally, would have produced three times himself in the next generation by way of passed on genetic material.
Now let’s look at the proposed advantage for Sodomites.
Sister + Husband -> Kid + Kid + Kid + Kid + Kid + Kid (two extras because of the advantage)
Genetically that makes:
Sister (1/2A) + Husband (0A) -> Kid (1/4A) * 6
Or, mathematically, the genetic equivalent of 1 1/2 brother. (6*1/4=1 1/2)
He has none of his own children, so all done.
Comparison of regular vs Sodomite: 3 vs 1.5 genetic material, 8 vs 6 children.
Just to get an equal amount of genetic pass down the sister would have to have 12 children!
Two sisters
When we look at insects that use this strategy, we tend to see lots of infertile insects to each fertile insect. But let’s see if the Sodomite advantage in humans would work in the other direction. Let’s give our ‘brother’ two sisters:
Regular reproduction
Sister + Husband -> Kid + Kid + Kid + Kid
Genetically that makes:
Sister (1/2A) + Husband (0A) -> Kid (1/4A) * 4
Or, mathematically, the genetic equivalent of one brother for each sister. Two sisters, thus a genetic equivalent of two brothers.
But in this example, the brother gets married as well:
Brother + Wife -> Kid + Kid + Kid + Kid
and genetically:
Brother (A) + Wife (0A) -> Kids(1/2A) * 4
Or, mathematically, the genetic equivalent of two brothers.
All told, the genetic equivalent of four brothers, and a total of 12 children.
Now let’s go for the Sodomite advantage:
Sister + Husband -> Kid + Kid + Kid + Kid + Kid + Kid (two extras because of the advantage)
Genetically that makes:
Sister (1/2A) + Husband (0A) -> Kid (1/4A) * 6
Or, mathematically, the genetic equivalent of 1 1/2 brother. Times two sisters, thus the equivalent of three brothers and 12 children.
Well, that’s a little better. You end up with only 3/4 of the genetic material, but at least the same number of children.
But this would mean that the Sodomite brother would have to succeed at increasing the successful reproduction two women by 50% each!
Three sisters?
Regular reproduction
Sister + Husband -> Kid + Kid + Kid + Kid
Genetically that makes:
Sister (1/2A) + Husband (0A) -> Kid (1/4A) * 4
Or, mathematically, the genetic equivalent of the brother for each sister. Three sisters, thus a genetic equivalent of three brothers.
But in this example the brother gets married as well:
Brother + Wife -> Kid + Kid + Kid + Kid
and genetically:
Brother (A) + Wife (0A) -> Kids(1/2A) * 4
Or, mathematically, the genetic equivalent of two brothers.
All told, the genetic equivalent of five brothers, and a total of 16 children.
Now let’s go for the Sodomite advantage:
Sister + Husband -> Kid + Kid + Kid + Kid + Kid + Kid (two extras because of the advantage)
Genetically that makes:
Sister (1/2A) + Husband (0A) -> Kid (1/4A) * 6
Or, mathematically, the genetic equivalent of 1 1/2 brother per sister, as above. Times three sisters, thus the equivalent of four and a half brothers and 18 children.
This is the first time where it might be argued that there is some advantage. There is less genetic material passed down, but over more children, so that might be argued could lead to an advantage.
But again we have to examine our presuppositions. This would have to mean that having a non-reproducing male in the extended family would manage to increase the reproductive success of three women by 50% each! That is a staggering advantage! Given how little energy the actual act of reproduction takes it beggars belief that this would be possible.
(The obvious answer to this quandry would be to have the brother impregnate the females, but this has other disadvantages; both the problem of inbreeding and in the lack of other males to take care of the offspring, defend the tribe, etc.)
And there is a corresponding disadvantage. For every non-reproducing male in a group, there must be one female (on average) who is either non-reproducing herself, or involved in a polygamous relationship.
Which might be a strategy. Suppose that only one male in a hundred was born with the drive and ability to breed. It is conceivable that a society could arise where that one male had a hundred females, and spent his day breeding them, while the 99 other males spent their days ensuring the success of the breeding population.
That might work. But as every young male on the outside of the pride knows full well, his own genetic success will be increased if he can manage to breed one of those females
Conclusion
So, good try but no banana. It simply isn’t true that Sodomy is valuable, even from the materialistic standpoint of evolutionism. The math doesn’t even come close to working, even given the most optimistic of assumptions.
[1] By ‘reproductive rate’ I mean children successfully raised till they can reproduce themselves. This might mean that the woman is better fed and thus can bring more children to term, that she and they are better protected so the children live through childhood, or any combination of effects.