So, I would just like to share some perspectives here, if that's alright.
I thought it would be easier if I just did diagrams. I'm better at diagramming concepts than I am at being a succinct typist.
First thing I wanted to talk about is DNA expression, kind of going along the thought track
@Rebis was on.
I learned a while back that my understanding of genetic inheritance was incomplete and outdated. A microbiologist explained to me how and why ancient and ancestral traits manifest in modern DNA. I felt like his examples were really illuminating for me so I thought I would share.
So there's two abstractions of the concept here.
Adam explained that DNA is passed from parents to children in sets or chunks - a grouping of genes. In school, I had learned that genes were sort of "melded together". Ie: If one parent was tall, and the other short, the kid might be genetically in-between the two. Adam explained that this perception is an incorrect way to view DNA.
The tall parent gives the child a set of characteristics, including the gene for "tall" and the short parent does the same. One of those sets will manifest in the DNA, and it will be accompanied by other characteristics that may seem totally unrelated - like having a unibrow.
We see this in cats. Orange tabby cats are usually docile and companionable, whereas calico colored cats have an attitude.
In any case, the first example expressed how a child's DNA makeup is like a computer program that their parents have added functions to. Within the program, there are many, many functions that are not called during execution - dormant genomes. Functions that are called will express the child's active genes at the time of birth, more or less. Other dormant functions may be called later as needed, and potentially in response to such things as environment, the food we eat, microbes, etc. (epi-genetics).
As we continue to breed humans, our programs are added on to. However, old functions are not removed.
So looking at the example on the right, this is an abstraction expressing how genes manifest in the individual, from an inheritance probability standpoint.
Adam explained these "gene sets" as being like dice. Parents add dice to the jar. You shake the jar, and dice are poured out at random. The dice the child gets are the activated genes the child is born with.
However, there's a catch. There's a lot of dice at the bottom that have accumulated throughout the years. Those dice are less likely to come out, because it's harder to shake them up from where they're settled in the bottom of the jar. (Obviously, we're assuming you're not tilting the jar and doing crazy things here). Even so, there's still a chance that an old dice from the bottom might make it into the final pour.
In that case, you end up getting ancient genetic expressions from long-dead ancestors.
It's more complicated than that, obviously, and apparently we still don't know a lot, from a scientific standpoint. DNA testing is helping to reveal more information, but we don't currently have enough participants to really capitalize on the data as we would like to.
But the bottom line, is that your chances of receiving traits from your ancestors are not non-existent, as people tend to think. Furthermore, they're not a "mesh" of ancestral traits, mixed in with a bunch of genes that came after that. They're very much still a "set", and that is why certain humans today can still express Neanderthal traits.
SO! Why do people want their own kids?
Well the chances that the child you receive will have activated genes that you're more likely to relate to, are much higher when the child is biologically your own. Mannerisms, appearances, diseases, and even behavioral tendencies like temper, in the child, are much more likely to be similar to you and your partner. Obviously.
Mammals we relate to are much easier to empathize with, communicate with, and form bonds with. The drive to build strong, loving relationships with the child is instinctual in - I think - both the genders. So it's natural for humans to feel a stronger innate connection to children that are biologically their own.
Disproving the "Stronger Genes" idea
We have, from my perspective, very little, if any evidence to indicate that your sexual selection and passing on your own specific genes yields genetically superior offspring. Here's why I think people believe that, and why I think they're very misguided.
It comes from darwinism and evolutionary biology. The concept is that we breed depending on the traits that are the best, and in doing so, we create superior offspring.
If that were the case, we should all be much more intelligent, beautiful, and physically superior than we are today, shouldn't we? None of the "then vs. now" data I've seen has a compelling connection to genes (ie: nature), over environment/nurture.
You see this in plants. Go for a walk. How have the new dandelions progressed since when you were a kid. What differences do you see? They are very prolific.
You see this in foxes. How far back do you have to go before you can point out an ancestor of the red fox that is inferior to the modern red fox we have today?
Here's the issue with genetic cleansing, genetic strengthening, and such. Genes come in sets. You can add new sets to the function, but if you do, older sets get shut off. If you breed with someone that has similar characteristics to your own, you're likely to also breed stronger tendencies for negative qualities, like diseases. That is why purebred dogs are less healthy than mutts, and that is why eugenics was dumb. Which the Germans knew, from their experiments with zoo animals...but ignored, for some reason. (I think scientists were afraid of the regime.)
As a last example, lets consider cats, because their colors make their genetics easier to understand. Cats can have different coats, their coat colors can indicate their sex (calicos are almost always female, orange tabbies are almost always male), and their coats can also indicate their temperament. Just like humans have races, cats have coat colors. Even so - a cat, is a cat, is a cat. A calico cat isn't exactly superior to an orange tabby. Abyssianian cats are extremely intelligent due to selective breeding, but with that, they also come with higher risks of negative genetic manifestations, of course.
To close off this "genes" point....
I don't actually believe that men are driven by a desire to "pass along their genes". I think that's a figment of scientists' imaginations. Evolutionary biology has a habit of wanting to explain every human behavior and characteristic, and I feel that it often misses the mark. A lot of aspects of darwinism have come into question. The "evolution" of genes was much more random than we ever realized - potentially much more determined by random mutation, than actual sexual selection.
If the primary motivation of the male was to pass along their genes, we wouldn't be a monogamous species. Yet, historically speaking, we have almost always had a monogamous construct in society. The reason for that is that humans have uniquely vulnerable offspring that take a very long time to mature. A human female cannot handle this burden unsupported by the male. Yet if the male's sole ambition is to pass along his genes, it behooves him to abandon said female to mate with as many females as possible, because even if the first offspring dies, his chances of having a high degree of breeding success are greater with more partners.
No, I think that the strength of the sexual drive is probably a side effect of necessary testosterone and primitive inheritance - simple side effects are common in genetics, apparently - and the primary motivation to breed with females is related to the much more modern, much more evolved need for a male to feel a sense of social acceptance and belonging. That is why men who do not receive the approval of women express such anger, frustration, etc. They will express similar psychological symptoms when deprived of the approval of men, or their parents. It's a deep need for social belonging.
A human can go its whole life and never have a sexual partner.
Take that same human and put them in social isolation, and they will go mad.
Take a baby, and give it all of its physical needs, and no human affection, and it will die. (Horrible study about orphans in, I think, Russia. I don't recommend it.)
The desire for approval and acceptance is much stronger than that of the desire to procreate. That is why human males are capable of being faithful to one female, and that is why our offspring, despite being completely helpless for the first 3 years of its life, or so, is able to thrive.
