Silly question, Callaway. It has already been answered. Age does not matter, except in the context of some modern facade of decency. We are animals, so, let's not try to counter that. If the young girls smell right - let's fuck 'em and keep them pregnant, until we find a younger one that bleeds. Nothing to worry about. It is natural. Of course, it is up to the parents to educate them and get them ready to fuck as soon as possible.
</sarcastic bastard>
My first thought was asking him if he would do her if she started her periods at 8, since he insists that we are just animals and I don't think animal instincts have any problems with incest, but I thought that might be going a little too far.
Animals (humans included) instinctively avoid incest. Usually, animals are strongly attracted to other organisms which are genetically similar to themselves, a phenomena known as
genetic sexual attraction, but there are a couple of mechanisms which counter this attraction in the specific cases of close relatives. The
Westermarck effect is an imprinting process in which the organism's sexual attraction towards other organisms which it grew up with, whether actually related or not, is inhibited. In humans, this manifests as unrelated children who're raised together having little attraction to each other, while siblings who were separated at birth are often very strongly attracted to each other through their uninhibited genetic sexual attraction. The other mechanism is the
major histocompatibility complex. This doesn't depend on imprinting, and makes organisms more attracted to other organisms who have a significantly different immune system to their own, as determined by scent.
These factors combine to make an organism seek out another organism which is genetically similar, thus providing a good chance of producing well-adapted offspring, but not related, so reducing the chance of inbreeding depression through double-recessive genes, and with a significantly different immune system, thus ensuring maximal immune system variability and effectiveness in the offspring.